!Teletext User Guide
Teletext v1.50
===============
What does this software offer?
------------------------------
* Fully compatible with the Ground Control and Octopus teletext receivers.
[including a modification program to allow compatibility with RiscTV, if
you have the Octopus !Teletext+]
* Script interpreter to make even better use of teletext; now includes
floating point variables for handling numerical data such as stock market
reports.
* Customisable 'preferred' pages listing, will allow you to keep track
of all of your favourite pages - however many there may be!
* Option to update your system clock automatically. If the channel you
choose offers full TSDP and is broadcasting in the same timezone as you
are configured, it will also set the date and 'daylight savings' for you.
* Save frames as a teletext file, sprite, ANSI, OvationPro, or plain ASCII.
Optional UUcoding if you'd like to send frame by email.
* Click on page numbers in the window to select that page, making teletext
as easy as point'n'click.
* Control window available in vertical or horizontal formats. This window
allows you to directly access ALL available pages, as well as HOLD,
REVEAL, LAST FRAME and more.
* Full keyboard control.
* Simple interactive configuration.
The configuration can be 'locked', providing a small measure of security
in, say, a classroom environment.
* Ability to switch the teletext palette on and off as you need.
Default is off, but switching it on and off again is only one menu
option away...
!Teletext even goes as far as remembering your current palette and
restoring it for you, in case it is not the same as the default WIMP
palette.
This facility is only of use in 16 colour screen modes, as 256, 32k and
16m colour modes support the necessary colours, and 2/4 colour modes are
monochrome.
* Help is available 'on-line' in the teletext browser. Just select P000.
* To view teletext saved frames, simply drag and drop into !Teletext.
Alternatively, just double-click on the saved frame.
* Compatible with other software: You can view teletext frames from any
compatible software...
The frame must be 1080 bytes in length containing the header, frame and
links data. The filetype is amp;112. The older Ground Control software
outputs compatible frames. I will be happy to implement convertors upon
specifications.
* Supports the Level 1 teletext specification, INCLUDING FLASHING TEXT.
* Several print methods, to get the best results whatever your printer.
Dependencies
------------
* You will need a Ground Control or Octopus teletext receiver.
[Given the loan of suitable hardware and driver modules, I will be happy
to modify !Teletext to support other devices]
* A driver module suitable for Ground Control teletext adaptors is included
with this software.
My gracious thanks to Colin Granville for permission to distribute his
code.
This module only works with the adaptor connected via IIC.
It is my understanding that the printer-port method does not work on
'newer' parallel hardware such as is used in the A5000 and later models.
It is not recommended that you use your existing driver module. However
it should be possible to use it provided you do not try to update your
clock and you do not try to read the channel ID (these functions use
facilities not provided in the original software).
* This software can be modified to work with the Irlam RiscTV card. You
will need the teletext upgrade, and also the Octopus !Teletext
application; both of which must be 'seen' before applying the
modification. Read the notes below for further information.
* RISC OS 3.10 with 256K memory, or better...
How to install
--------------
1. Unarchive somewhere convenient...
2. Run the program. Set up tuning and defaults.
3. Use!
Notes on drivers for Octopus/Ground Control receivers
-----------------------------------------------------
The Teletext module supplied within !Teletext should work with the teletext
hardware as was sold by Ground Control, and latterly by Octopus Systems.
It is recommended that you do NOT use your existing driver if at all
possible. However if it is necessary (ie, you use the parallel port to
connect your receiver), then copy the existing module into this !Teletext
application, and rename it "Teletext". You may also need to edit the !Run
file so it doesn't say you need a newer Teletext module...
Please be aware that !Teletext uses some newer features that were not
provided with the original drivers. It is thought that the older drivers
should still work, provided that you do not attempt to read the channel ID
or update your clock.
If !Teletext crashes with an error such as "Unknown SWI" or "Unknown
Teletext operation", this is because you're trying to do something that
your driver doesn't support.
IMPORTANT: If you set "Check clock" as a start-up option, and you are
using the old driver, you may find that !Teletext crashes on
start-up with the "Unknown Teletext operation" error. In this
case, you will need to delete the !Teletext "Configure" file.
This will prompt !Teletext to restore the default settings,
which does not check the clock...
Notes on the Octopus driver and RiscTV cards
--------------------------------------------
This software can be used with the Octopus Systems Teletext+ module, and
an Irlam RiscTV card.
In order to do this, amend the !Run file to run "TTX+patch" before running
!RunImage (simply uncomment the appropriate lines in the !Run file).
Please note that you should NOT attempt to save the patched Teletext+
module back in to !Teletext+, as the patch does things to the Teletext+
module that prevent it from working with !Teletext+. Please refer to the
"TTX+patch" program to find out what it does...
Notes on other hardware
-----------------------
Apparently the teletext driver will work with "standard IIC teletext
hardware", for example:
Computer Concepts teletext receiver
DezignIT's teletext receiver
Ground Control/Octopus receiver
Irlam's Teletext card
Morley Teletext unit
I have not tried it with anything other than the Ground Control unit.
I don't know about the Acorn teletext receiver. You could try...
I have had reports that it works well with the Morley unit, though I do not
know how it was set up.
If anybody has any old teletext hardware for ANY Acorn machine, please send
it to me! It would be a great benefit if some sort of driver software was
included, but don't worry too much if it's been lost over time.
Setting up IIC (GC/Octopus units; techie)
-----------------------------------------
Please be aware that this is a bit of a bodge, so the usual disclaimers
shall apply. Provided you are careful, you shouldn't fry anything. But if
you are the least bit unsure.....DO NOT DO THIS.
THIS INFORMATION IS GIVEN IN GOOD FAITH, AND I TAKE NO RESPONSIBILITY FOR
AN INACCURACIES THAT MAY OCCUR. NO LIABILITY WILL BE ACCEPTED FOR ANY LOSS
OR DAMAGE, HOWEVER CAUSED, AS A RESULT OF FOLLOWING THESE INSTRUCTIONS.
Please also refer to:
1. The documentation provided with your teletext receiver, it may provide
you with details of the socket wiring. If not, refer to details of any
of the IIC devices and use a multimeter to check which pin is which.
2. Any of the technical documentation for your RISC OS computer. The
various "Technical Reference Manuals" contain details of the expansion
ports. Failing that, the general "Expansion Specification" should be
available from the mirror of the old Acorn FTP site (you should find
this at http://www.riscos.com/ ), or on various AcornUser CD-ROMs.
Always check what you have done with the proper documentation before
switching your computer back on.
TURN YOUR COMPUTER OFF!
Open your computer and locate your podule backplane. If you have a spare
slot, you may be able to push your wires into the holes (though this is not
recommended). Otherwise, you'll need to strap them onto the backplane
connection of a convenient podule. The exact method depends upon the type
of wire you use. I recommend soldering as it is less likely to come
'unstuck' to leave wires in danger of dangling down onto the motherboard.
My preference is to use an Econet drop lead, as the DIN plug is the correct
type for the teletext adaptor. Remember, IIC is supposed to be used inside
videos and television sets, and is used inside your computer. Keep the
leads as short as you can.
Looking at your decoder, you have a five-pin DIN socket in the middle of
the front panel. It should be marked "Data":
Not connected O O +5V
IIC clock O O IIC data <-- Looking at the
Ground O adaptor from the
FRONT.
I only connect the IIC data/clock and the ground.
On your podule backplane, there are two rows of pins. The bottom set is
row A, the upper set is row C. Some podules (old style co-processor or new
style with DMA) have the middle B row as well.
IIC is available on pins 19 (clock) and 20 (data). Ground is on pin 26, or
pin 1 if you prefer. All on the C (upper) row, where it is easy to get to.
Check your wiring carefully. There are a lot of system signals, including
-5V and +12V on the podule bus (pins 2 and 32 respectively), so don't make
any mistakes here. Also ensure the wires are not touching.
You will probably get away with a frozen system if the IIC wires are
touching nearby wires (data bus, podule select, DMA...) but if you use pin
1 for ground, -5V is right next to it. This will cause severe cookage.
Leave the teletext adaptor unconnected and power up. All should be fine.
Switch off.
Connect the teletext adaptor and switch it on. Then power up the computer.
If you notice anything odd, like your monitor fails to lock into the video
signal, or most of your modules have vanished - even the ones in ROM, then
simply switch off and swap the IIC clock and data pins. If this is wired up
incorrectly, RISC OS is unable to read your CMOS RAM settings.
** IMPORTANT: If, upon connecting your teletext adaptor, your RiscPC seems
to die - no valid video signal, no beep, and dead keyboard;
give it a hardware reset (the button 'round the back) and
watch the keyboard LEDs carefully. They should flash four or
five times, then the keyboard becomes non-reponsive.
This means your IIC data/clock signals are incorrect.
It seems the RiscPC panics more than my A5000 did, in this
situation.
** IMPORTANT: Upon disconnecting your teletext adaptor, even after
correcting the backwards clock/data, your RiscPC may still
refuse to start up - as described above.
Switch the machine off, count to twenty. Hold 'R' and then
switch back on (with 'R' held down). You should get a beep
and working keyboard, but probably no valid video signal.
To get one:
Press F12
Hold Ctrl and tap G. You should hear a beep.
Enter the following (typing blind, so take care):
*Configure MonitorType 3
*Configure Sync 0
*Mode 28
Reboot, holding shift and keypad-*.
You should now be in the command line. You will need to
restore your CMOS RAM settings. For me, I'd type:
*LoadCMOS $.Utilities.!SaveCMOS.Saved
Please check your computer's clock, as it might have reset
itself to 1996. You can use !Teletext to set the clock
accurately. :-)
Like I said... it seems the RiscPC panics more than my A5000
did, in this situation.
That done, you can dangle the lead out the back of your computer in a nice
and inelegant fashion reminiscent of the days of the BBC micro when your
status as a user was judged soley upon how many wires protruded out of the
machine. I suggest you give the wire a small hole (such as between two
podules?) and tie a knot in the wire, so if the wire is tugged, it doesn't
do damage inside your machine.
I prefer IIC to the parallel option as my parallel port is in use (Zip
drive and printer) and, besides, I lost the lead for the decoder years ago!
The supplied teletext module expects an IIC connection. It will not work
with parallel port wiring.
Setting up the software
-----------------------
Assuming you have the Ground Control software, you will probably have
already tuned in. If so, you can use the 'GCConv' program (in the Utilities
directory) to create a default configuration file for you. This assumes
both !Teletext and the older Ground Control program have been 'seen' by the
filer.
If not, then run !Teletext and click [ADJUST] on the iconbar icon.
The viewer window will open, and the configure window will open in front
of that.
Select the required channel using the up/down toggles beside the 'Channel'
icon. Default is '1'.
Enter a channel name in the 'Name' icon space. Press [Return] to get the
name 'accepted'.
Then use the up/down toggles by the 'UHF' icon to tune in to your channel.
Once some form of data is receivable, you'll see the viewer window (in the
background) displaying what is received. Use the header line to make sure
your tuning is spot-on.
Usually you won't need to bother with fine tuning. However if you are
trying to tune off a VCR or satellite receiver, you may find that the
output is not bang on a channel.
Tuning is between 21 and 67 UHF, and this wraps around.
Fine tuning is between -50 and 50, and this wraps around.
Don't know the channel tuning? Use the 'Automatic Search' to search for
channels for you. Click SELECT to begin searching, and click ADJUST to
stop search. It will stop on its own once a channel has been found.
Some devices, such as satellite decoders, may not be picked up by the
tuning search. If the search fails, you will need to tune manually.
Change channels, and repeat the tuning as required.
Start options...
When !Teletext starts, you can have it automatically check your clock for
you. Select "Check computer's clock" if you wish it to perform this action
for you. "No messages" means you want your clock checked and updated, but
you don't want to be told about it. At all.
The "Open viewer window" option will make the teletext viewer pop up as
soon as the program has initialised, without you having to click on the
iconbar icon.
To aid this, the "Default channel" selector chooses which channel you are
tuned to at start-up.
The cache...
!Teletext offers a cache. This will not make new pages appear any faster,
but it will make previous pages appear instantly. This is useful when, say,
you are reading the television schedule with several frames (thus meaning
the "Last frame" icon won't work) and you wish to go back to the television
guide index to see what else to look at.
Without the cache, you would need to wait for the guide page to roll around
to then select the particular page you are interested in. With the cache,
it comes back instantly.
Select the "Cache found frames" option to use the cache.
The "Clear cache upon exit" option wipes the cache when you quit !Teletext.
This may not be necessary - see below.
You can set your frames to 'expire' after a certain time. When !Teletext is
making a list of the cache entries, it will warn you pages may be getting
old if they are over 12 hours old. You, however, can control the expiry
time as you see fit. 12 hours is recommended, however.
Set the expiry time to 0 hours to disable automatic expiry.
Notes:
The cache is automatically 'tidied' when you start !Teletext, and all
out-of-date frames are removed. If you have a reasonably short expiry
time (such as less than 24 hours) then you need not choose to clear the
cache upon exit.
If you disable the expiry, !Teletext will return from the cache the first
matching frame discovered. It cannot 'know' when a frame is too old as
you do not specify what you consider to be 'old'.
The script interpreter manages it's own virtual cache within the main
cache. Basically, a flag is set to mark frames as belonging to the script
system. Therefore the script will make no use of entries already in the
cache. The viewer, however, is less discriminating and will make use of
frames fetched by the script.
Script...
There is only one option, whether or not to allow scripts to be run.
Speed...
The speed that !Teletext operates is user-configurable. This allows you
to make the most appropriate choice of whether to have smooth desktop
operation, or fast Teletext updates. In general, you don't really need to
see every digit roll by on the page header (don't worry, if you didn't
see your chosen page number, it'll still be retrieved - nothing is lost,
it just keeps you informed less often!).
You have three options:
Flash update : This is the rate at which screens with 'flashing' text
will be redrawn. In other words, this is the delay
between flash on and flash off, and vice versa. The
default is 50cs, but I personally prefer 45cs as it is
just a touch quicker.
Flash ticks can be set from 5cs to 500cs in 5cs jumps.
Main update : This is the rate at which the main "is a page ready?"
loop runs. This should, for good results, be set to 50cs
as well, but I prefer 60cs as you won't really notice an
extra 10cs, but it gives your computer that much extra
CPU time.
Main ticks can be set from 5cs to 500cs in 5cs jumps.
Null update : If you 'freeze' !Teletext with flashing text, it will
instruct the desktop to pass control to it at the speed
you have told it to for 'main' update.
If you 'freeze' !Teletext with no flashing text, it will
instruct the desktop to pass back control only once
every 'x' centiseconds. As you'd be passing back control
to do nothing, you can set quite a high figure here;
like 6000cs (a minute).
Null ticks can be set from 100cs (a second) to 12000cs
(two minutes) in 100cs jumps. Default is 6000cs.
If you set your flash update to be quite small, like 10cs, and your main
update to be larger, like 100cs, then you may notice two things:
1. The page header updates more frequently than once every second
2. It might take up to a second between your page 'arriving' and you
getting to see it.
This is because, when displaying flashing text, the frame header is
ALWAYS updated, so that the page sequence always runs in the correct
order...and the time too! However, the main "is a page ready?" check is
only happening every second. This explains the delay.
If there is no flashing text, the header will, obviously, slow down to
the normal 'main' update speed.
I should clarify how the polling occurs:
'Normal':
Teletext claims EVERY poll cycle. This means the desktop hands
control over to Teletext every single time it cycles around the
available programs. It needs to do this, because Teletext has a high
degree of "stuff is happening in the background". However it does not
actually need this much processor time on a fast machine. If the
pages are coming in every 40cs (like on CNN), then there's little
point in checking for a new page every 5cs. You'll be checking eight
times more than is necessary.
So what we do is to ask the desktop to pass control over to us each
time around, and we work out if we need to do anything now. If we do,
then we do it. If not, we say "okay, I'm done".
We make two seperate checks. The first is for the flash update. If it
is time for a flash transition, we change the displayed frame for the
flash or non-flash one, as applicable.
Then, we check the main update. If it is not time for the main update
we'll return control to the desktop. Otherwise, we'll do the update
if it is ready, and a few other things too.
Script processing is a special case. Basically, every poll cycle is
passed on to the script interpreter, and for each poll it will
execute one line of script.
'Frozen':
Claiming every poll cycle is 'expensive'. It isn't quite as simple as
the desktop saying "here teletext, do something". It has to 'map' in
the teletext software (every application 'believes' it is loaded at
amp;8000 in memory, but in truth only one thing can be there at any one
time, so each application is 'mapped' every time it is called to run)
and this takes time, both in setting up the memory map, and in
generally shoving internal memory and tables around in order to do
it. For this reason, the desktop has an 'idle' mechanism, where an
application can say "don't bother calling me until...". When Teletext
is 'frozen', very little will happen in the background. In fact, to
be precise, only one thing will happen in the background... Flashing
text.
If the page you are looking at contains flashing text, then Teletext
will tell the desktop only to call it according to the main update
rate. Yes, this may be slower than your flash rate, accordingly your
page will flash more slowly.
If you are not viewing a page with flashing text, then Teletext can
be entirely user-responsive ... there are no background things to
worry about, so it will tell the desktop to call it according to the
null update. You have to give the desktop a time, so you might as
well just say "in a minute!". This will NOT affect your use of this
software, as the desktop will always call Teletext when "something
happens", like an icon click or you choosing a menu option. The time
is used for when "nothing happens". You'd be surprised how much
processing time is saved by NOT loading an application for it to say
"I'm not doing anything".
'For nerds':
As well as displaying the rolling header, we need to call a SWI to
see if a new page has arrived, and also to time the flashing text.
Therefore, I feel my method is the best trade-off between time delays
to the desktop and time delays to the user. This is particularly
notable in the switch between 'normal' polling and PollIdle. However,
as a lot of things occur in the background (like the header change,
or the 'page ready'), it is not practicable to PollIdle all the time.
I did save a little bit of speed on a 'clean' system by PollIdling
for 15cs, but when lots of tasks were loaded, it actually ran more
slowly to do that - as the idle was not coming back within 15cs and
it was 'wasting' time working out the next 15cs delay time. I suspect
the situation would be similar on slower hardware.
A possible alternative is to use the PollWord system, and have a
small module time the flash update and also check if a page is ready,
and set a PollWord accordingly. However I feel that this is a rather
unnecessary complication - extra modules to load, callbacks, etc...
I have Teletext running as I type this. The system is not that laden with
it. There are slight pauses as the new page is fetched, but given the fetch
is ~1.5K over IIC, there's nothing I can do about it.
Page 100, CNBC, flashing text, refreshed every five seconds:
Flash update 10cs, main update 30cs; Teletext uses ~80% processor time.
Flash update 30cs, main update 60cs; Teletext uses ~65% processor time.
Flash update 75cs, main update 75cs; Teletext uses ~55% processor time.
Page 182, CNBC, non-flashing text, refreshed every twenty four seconds:
Main update 30cs; Teletext uses ~48% processor time.
Main update 60cs; Teletext uses ~44% processor time.
Main update 75cs; Teletext uses ~40% processor time.
Frozen / not in use, viewer window closed, or open with non-flashing text:
Null update 100cs; Teletext uses 2% processor time.
Null update 6000cs; Teletext uses 0% processor time.
Frozen, viewer window open with flashing text:
Teletext uses 6% processor time (main update 30cs).
Finally...
If you are a school, or have young kids <grin>, you might like to click
on 'Lock configs' to lock out the configuration window. To unlock, you can
either delete the 'Configure' file or use the supplied 'UNLOCK' program.
This option is only available if you toggle the window to full size.
Happy? Then click 'Save configuration'.
Close the configure window to end configure mode and bring back the control
window.
The iconbar icon
----------------
Click SELECT to open the viewer window.
Also, hold down Ctrl while clicking to call up the Preferred Pages list.
Or, hold down Shift while clicking to call up the Cache list.
Holding Ctrl and Shift while clicking will call up both lists.
Click ADJUST to enter configuration mode.
If the Teletext receiver is not operating (ie, not connected/plugged in),
you'll be told of this. In this case, you can still use Teletext in an
"off line" mode, whereby dragging/double-clicking files will open them in
the viewer.
Clicking MENU...
.--------------.
| Teletext |
|==============|
| Info > |
| Check clock |
| Help |
|- - - - - - - |
| HardwareTest |
|- - - - - - - |
| Quit |
'--------------'
Info:
Tells you the software version.
Check clock:
This will compare the received clock signal with your system clock, and
allow you to update it if they differ.
Help:
Shows you this text.
HardwareTest:
This tries to read from the three primary parts of the teletext decoder
(the teletext decoder, the tuner controller, and the video processor).
This was added so if your teletext decoder is connected, but not
responding, you can test that it is running correctly. Alternatively, if
you just like fiddling with menu entries... :-)
This will report "Your teletext decoder is responding correctly." if it
is, and up to three error messages if you turn it off. If it is on, but
acting up, you should get an error message to aid you in diagnosing the
problem.
Quit:
Please tell me you don't want to know what this option is for! :-)
Clock update
------------
!Teletext will update your clock if it is more than five seconds out. It is
recommended that you always update your time from the same channel as
channels tend to differ in their perception of 'real time'.
The time adjustment is taken from the TSDP broadcast every second by most
stations. This is a very accurate way to set your clock, which is much
better than trying to decode the rolling time in the frame headers.
If your computer's timezone is correctly configured and you are setting
your clock from a broadcaster in that same timezone, then !Teletext will
also set your computer's "daylight savings".
Here is an example for the United Kingdom:
Territory 1
TimeZone +0:0
And you'll be watching BBC, ITV, Channel4, Channel5, or a plethora of Sky
services...
Here is an example for central Europe:
Territory 1 <-- this is less important, so it could be 6 or 7, say...
TimeZone +1:0
And you'll be watching RTL or something on one of the Astra analogue birds.
Provided your timezone (and, territory if non-standard) and broadcaster
match, this system should work anywhere in the world.
Please do not attempt to set a UK timezone from a CET station, or vice
versa. !Teletext tries to check the time zone offset broadcast matches one
of your available time offsets.
Some stations (such as CNN, I'm surprised) do not broadcast a valid time
offset. !Teletext will warn you of this, then ignore the time zone. The
clock and date will be updated. Other stations (such as Germany's MTV, I'm
even more surprised) broadcast a valid and correct time zone offset.
Some of the 'lesser' stations (I'm afraid this includes Viva and VivaPlus)
don't broadcast a TSDP at all, so clock updating is not possible with those
stations. Please select another...
When I load !Teletext, I set my satellite decoder to German MTV, then I
let !Teletext start up. It updates my clock with no messages. Sometimes, if
I look very closely, I can see the display in !Alarm hiccup ever so
slightly as the new time is added. Or, the time rolls according to DST.
I have been informed that the Octopus Teletext+ has a time zone offset set
up in the !Run file, and it (v7) apparently only really works in the UK.
Come on Paul! You can do better than that! :-) Use the Territory module!
Viewer window
-------------
This is where the frames received via teletext are displayed. The header
line constantly updates and the frame itself is redrawn every ten seconds
or so.
This window is, more recently, referred to as the browser window. So if you
see references to "viewer" or "browser", I mean the main window that you
read the teletext frames in.
As soon as this window is opened, !Teletext claims the "input focus", thus
allowing you to use keyboard controls if you find that easier or quicker.
Within this window, you can click the [SELECT] button on a frame number.
This will tell the teletext system to hunt for this new page... It is
easier than using the control keypad. :-)
You will notice many pages have a line down the very bottom with text in
RED, GREEN, YELLOW and CYAN. This is called 'FastText'. It is a series of
'hotlinks' to other related pages. You can click down the bottom of the
window to use FastText.
Note that you do NOT click on the text itself. The bottom line of the
window is divided into four equal zones. The first zone, on the left, is
for the RED link. Then another zone for GREEN and so on. The software
cannot tell where the FastText prompts really are... Maybe in a later
version. :-)
Like always, you can click on [MENU] to bring up more functions...
.--------------.
| Teletext |
|==============|
| Freeze |
| Save frame |
| Notes |
| Palette |
| Configure |
|- - - - - - - |
| Print > |
|- - - - - - - |
| Cache > |
|- - - - - - - |
| Open 'Pages' |
|- - - - - - - |
| Preferred |
| Script > |
| Channel ID |
'--------------'
Freeze:
Selecting this will freeze the teletext system. Useful if you want to
switch it off for a while without quitting the application. When the
system is frozen, a little tick will appear beside this menu option.
Click again to 'defrost'.
With my tasks idling, I monitored !Teletext taking 75% of the available
time when it was running. When frozen, this dropped down to zero as the
page headers were no longer being updated, the pages no longer refreshed
and the window no longer redrawn. When frozen, !Teletext only polls once
a minute.
Note that this is a purely subjective assessment. There was no noticable
delay in system use as it was available time. It also depends on the
other tasks in use. Measurements taken with Ran Mokady's !Usage.
Save frame:
This will open a window with options for you to store the current frame
on disc.
Notes:
This will open a window in which you can make notes as you are going
along.
NOTE: Do not click in the viewer window with ALT held down if you have
notes. Doing so will fill the notepad with status information on
the current frame.
Palette:
This will active the 'teletext' palette, updating the WIMP colours to
that used by teletext (that olive colour is actually magenta!). When you
select this, your current palette is stored. When the teletext palette
is in use, this option is ticked. Click again to revert to your normal
palette.
This option is only useful in 16 colour screen modes. !Teletext will warn
you if you try to set the palette in another mode. You can, however,
restore the original palette in any mode.
Configure:
This will close the control panel and open the configuration window.
Print:
This brings up a sub-menu with two options:
.-------------.
| Print |.-------------.
|=============|| Print image |
| Text only ||=============|
| Image > || Enhanced |
'-------------'| - - - - - - |
| Normal |
| Inverted |
'-------------'
Text-only will print the current teletext frame as pure text.
Enhanced will print the current teletext frame as seen on-screen,
except the background will be white and the white text a
mid-shade of grey. This is so that the teletext frames can
be printed roughly correctly in either monochrome or
colour without wasting too much ink.
Normal will print the current teletext frame as seen on-screen,
exact colours. This, obviously, will use a fair amount of
black ink (or toner) so obviously isn't preferred for
normal use.
Inverted will print the current teletext frame as seen on-screen,
but with a converted palette (inverted greys) which
should make it print better, and with less ink. The
difference between this an enhanced is there are no
colours (it is monochrome), and the colours have been
swapped so light is dark and vice versa. This may give the
best and most solid print of textual information, but
things using colours (ie, adverts) may look bizarre.
The print system uses the RISC OS printer drivers, and will invoke the
!Paint application in order to print the bitmap images.
Here's a little "easter egg". You can 'see' how these pages (should)
appear when printed by doing the following:
1. Ensure your chosen page does not 'flash'.
2. HOLD your chosen page.
3. Open the viewer menu, and drag it off of the page. Go to a print
option, like, say, "Print -> Image -> Enhanced".
4. HOLD DOWN THE ALT KEY and then click on the print option.
The teletext frame will be redrawn in the colours that would be used to
print. Causing a redraw, any method, will redraw in the normal teletext
colours.
Cache:
These options are explained in the section describing the cache
facilities.
Open 'Pages':
Will open "<Teletext$Dir>.Pages", the default save path.
Preferred:
This will display your "preferred pages" list. Double-click on a page to
select it in the viewer, or use the menu to add or modify entries.
Script:
This will run a script. Open the submenu and choose a script. If you
wish to write your own scripts, please read the accompanying script
guide.
To cancel a script, click the iconbar icon.
Sometimes, a script may single-task. You can tell this by your pointer
turning into an hourglass. Hit Esc to cancel the script, in this case.
If you do not have the script guide, you can download a copy from the
teletext website. It is available as a StrongHelp document.
Channel ID:
This will display the TSDP channel identification. Please note that it
may have odd spacing... Have you ever seen the channel name banner pop up
on a fairly modern TV when changing channel? Well, that's what the TSDP
name is for, and why it might have odd spacing. Some broadcasters like to
'centre' their idents.
You can drag a saved teletext file into !Teletext to view it. All current
teletext operations will be suspended. The receiver will be 'frozen' and
your saved page will be drawn on the screen.
Control window
--------------
The control window allows you to select frames, channels and control
various other aspects of the teletext system. By using the menus, you can
select a vertical (default) or horizontal control panel, and you can
choose 'preset' pages, if any are configured.
0 1 2 3 4 5 6 7 8 9 A B C D E F
These are your frame/channel selection icons.
C
This sets the system into channel select mode. The next icon you select
(from 1 to 9) will select that channel for you and initiate scanning for
frame 100.
P
This sets the system into frame select mode (P is for Page). Unless you
click on 'C', the system stays in frame select mode so you don't have to
click this each time. It can also be used to cancel channel select if
you clicked on 'C' by accident...
Any frame number between 001 and FFF may be selected. You must enter
leading zeros. As you may have noticed, this teletext system offers you
direct access to all 4095 possible frames.
Note that teletext magazine zero (page 0xx) is invalid. Try it on any
teletext television - an initial zero will be changed to an eight.
Once three numbers have been entered, the system will search for that
frame.
If the clock stops, or the header line vanishes, it is possible the
magazine you are looking for doesn't exist. If the numbers at the top of
the frame wrap around a few times then it is likely the frame you are
looking for doesn't exist.
Some channels loop around all pages. Some loop only in the magazine you
are looking in. This is controlled, somehow, by the broadcaster.
Hold
This will hold the current frame so the further frames (say, in a news
reel) don't overwrite what you are currently reading. Note that further
frames will not be stored, you will have to wait for the cycle to loop
around again.
Reveal
Sometimes brain-teaser type things ask you questions and hide the
answers. Use this to display these hidden things.
Local index
All frames are part of a magazine. We all know frame 100 is the entry
screen and frame 199 is (usually) a full index. However neither is
really appropriate when you are viewing what is on Meridian and you want
to look up information on what is on TV now and next. So click this icon
to go to the local (in this case, the television magazine) index.
It appears that many satellite broadcasters simply set this option to
redirect you to the entry index (frame 100). How very useful - NOT!
Last frame
When you select this, the system will enter 'Hold' mode, and the current
and last frame will be swapped. This is useful if you just missed that
last sentence, or if you selected the wrong frame by accident.
I repeat again, this will select 'Hold' mode automatically.
Save frame:
Click this icon to bring up the Save window.
100
Click this icon to go to the default entry index frame on all services.
Some satellite broadcasters, such as Bravo/*Living, used to pop up a page
telling you the main page is p200. Go figure.
199
Click this to go to the full index frame, on most services.
Again, this differs on some satellite broadcasters. QVC used to output a
series of test pages on 199.
Keypresses
----------
You can control the teletext viewer by clicking in the viewer window (not
on a teletext page link) to give it 'input focus' (the highlight).
Then, certain keys allow you to manipulate the viewer...
0 - 9 Select a page, or a channel in channel mode.
^C Channel selection - type ^C then a number from 1 to 9.
^P Go back to page selection from channel selection, if you do not
want to change channel.
^F Toggle Freeze.
^G Print (in graphics mode).
^H Toggle Hold.
^I Go to index (normally page 100).
^K Keep this frame (and this channel) in your preferred pages list.
^L Go back to previous frame.
^Q Close the viewer.
This does not 'quit' !Teletext, only the viewer.
^R Toggle Reveal.
^S Open Save frame window.
^U Toggle Palette (only in 16 colour modes).
^T Print (in text mode).
+ Select next frame (you may also use cursor up).
- Select previous frame (you may also use cursor down).
<-- Cursor left and Cursor right will step through the available
--> subframes. Please note that this does not 'skip' missing ones.
For example: You have subframes 1, 3, 4, and 5 and you are
currently looking at #4. You can use the left and right cursors
to look at subframes 3, 4, and 5. You cannot look at subframe 1
until subframe 2 has arrived (to complete the sequence).
!Teletext will beep if it couldn't find a subframe.
[this will not work if you aren't using the cache]
Esc Abandon current selection.
The Notes window
----------------
This little window is where you can jot down notes as you wander through
teletext. It is a set of ten normal RISC OS writable icons, so you can use
the usual operations like ^U to wipe that line... Cursor up/down will move
around the lines. Press Return for the next line. There is no word-wrap.
And it looks peculiar in a Desktop supporting the global use of outline
fonts (WindowManager v3.22 or later).
The single menu option 'Clear' will reset the notes to a blank window.
It is as simple as that. :-)
If you pressed ALT and clicked in the viewer window on purpose or by
mistake, you'll have noticed the Notes window pop up with lots of
information. I'll explain it all to you...
Line 1 :
This is the program name and version.
Line 2 :
This is the date of this version.
Line 4 :
This shows you the current channel settings. Firstly the channel number.
Then the channel name. This is terminated early if it's a long name.
Next comes the channel tuning in UHF channels and fine-tuning offsets.
Finally an 'I' is appended if the channel is set up to use the IRCS.
Line 5
This shows you the current frame and subframe. You'll notice some frames
have subframes even though there is no conventional '1/10' type
indicator. An example of this is the entry frame 100, where the menu
changes every so often to highlight what is available.
Line 6
This shows the link frames for the Red, Green, Yellow and Cyan frames.
Now you are a trustable person aren't you? Good... I thought so.
Untrustable people might use a facility like this to cheat at Bamboozle
(oh! the shame! the shame!). <giggle>
Line 7
This shows the local index linked frame and the telesoftware catalogue
frame.
TeleSoftware was transmitted quite regularly on BBC2 until about 1988
or so. Then it stopped. Shame really, but I suppose downloading a
modern program (like !Teletext itself?) via teletext would take longer
than the week the program was available for...
It is a shame it can't be used by local broadcasters for community
information and revision aids for students. For example, a CSV file
listing 'important numbers' (Telecom fault reporting, Samaritans, local
hospitals etc etc) or a CSV file with the periodic table of the elements.
Line 8
Shows the language of the frames.
Line 9
Tests the frame to see if it arrived intact. A number of times it flags
an error, the actual frame looks okay. This is because it performs a
full and complicated computational check on the data. I don't think I've
yet had a frame come in and CRC pass.
Line 10
When you last did the ALT-click bit...
The Save window
---------------
When you open the save window, and when new frames are received, the
program supplies you with a default file name made up as follows:
{channel}_{frame}-{subframe}
Use this name or enter your own. Then select the save type, be it teletext
or sprite or ASCII. Finally, drag the icon to a directory viewer or click
Okay to save to the Teletext frames directory inside !Teletext.
RAMtransfers (sprite into paint etc) are not supported, but <Wimp$Scrap>
saved files will be Filer_Run... An oddity of my method is if you drag a
sprite to !Paint, it may give an error of the filename.
The most efficient way to save a file is to use the Teletext file option.
Then to view the file and possibly save it again as a sprite or ASCII, you
simply drag the saved teletext file back into the !Teletext application.
If you save your frame by pressing Return, the input focus will be given
back the the viewer afterwards.
Printing your teletext frames
-----------------------------
There are four options available to you.
Firstly, you can print the Teletext frame as pure text. This is the
quickest method, uses the least ink, gives the most dire output if the
page contains a lot of 'graphics'.
The Sky One logo looks something like:
pp`0``0 0 h,,,,,,,,,,l
ju"ju>*}h% "x|0ht|t x|2
+}j7} k7 j j j j j ~
*,'*%*%*% "o~'j j "o|<
*,,,,,,,,,,.
Secondly, you can print the Teletext frame as you see it. On a colour
printer, it will be printed in full colour. On a monochrome printer, it
may look a bit weird - with reds and blues both printed as black, so...
The third option is a converted print. This is for monochrome printers and
those who wish to save their ink. The whole image is converted to
four-shade monochrome and then inverted. The colour mapping was chosen to
give the most satisfactory results with ArcFax. So yes, you can even fax
teletext pages around!!!
The final, and possibly most desirable version, simply removes the black
background and darkens the white to be a mid-shade of grey. Thus, colours
are pretty much preserved and it should look 'correct' when printed.
The print system uses the RISC OS printer drivers. It is NOT able to print
directly to the printer port, as this defeats the point of a multi-tasking
resource. The pure text option can be printed by the printer driver
itself. The image options, however, require the assistance of the !Paint
application, so expect to see this pop up during the print operation.
*ALL* of the print options work by instructing the !Printers application to
print, and letting it (!Printers) get on with the job. Therefore, the usual
method of loading the drivers for things like DTP (load !Printers, choose
your printer, then quit the front end) will *NOT* work here. The front-end
must be loaded.
Yes... I know it is pretty easy to generate a printed page. Maybe in a
later release...
Using the cache
---------------
The cache is designed to make the teletext system appear more responsive.
It will not make the frames download faster.
The benefit of the cache can be explained as follows:
a. You go to Sky's television index (120).
b. You go to the "Now and next" (124) and watch both subframes.
c. You go back to the index (120).
At point 'b', you have watched both frames, so the "Last frame" option will
not take you to the index.
So at point 'c' you might have to wait for the television index to appear.
Not so with the cache, it comes back instantly.
Please note that the main index (100) is never retrieved from the cache.
Please also note that unlike other software, the cache is entirely disc
based. Not even the entire cache index is kept in memory at one time. This
has a potentially severe performance hit for floppy-only systems, but
weighed up against a smaller memory requirement on harddisc systems. A
trade-off for floppy users would be to place the cache in a RAMdisc, you'll
probably need to modify "netsetup" in this case.
You have five menu options to help with cache management:
Show cache:
This displays the cache list window. You can double-click on ANY valid
frame shown, even expired frames, to show them in the viewer.
You can also hold down Shift and click on the iconbar icon to open the
cache list window.
AutoScan:
This is possibly the most useful of the cache options. When you are not
going to be using !Teletext for a while, you can set it to autofetch as
many frames as it can in the time that you give it. It will fetch frame
101, then 102 and so on (it will only fetch each number once, so
subframes will not be stored).
When you come to use !Teletext, provided it is within the configured
time-out, your frames will appear instantly, so you could browse the
news and television highlights (for example) without waiting for the
frames to be fetched. As you select a frame to read it, !Teletext will
search for any subframes, which will begin updating in the usual way.
As AutoScan is a background operation, opening the viewer window will
cancel AutoScan. If a frame cannot be fetched in fifty seconds, it will
be skipped and the next frame searched for.
It is recommended that you flush the cache before AutoScan.
An alternative, which provides more control, is to write a script which
can change channel, and fetch exactly the pages you require.
List index and Print index:
These options will create a list of the contents of the cache index.
This was primarily a debugging feature, but has been retained as it can
be useful to look at. Or fun. If you are in to really geeky things. :-)
The "List" option will load the index listing into !Edit, and the
"Print" option will cause the RISC OS printer drivers to print the
listing.
"Entry" shows which index entry this is.
"Channel" and "Frm / Sub" show the channel, frame and subframe that
this entry is.
"Time" shows the time (according to your computer) that this frame was
cached at.
"Offset" shows you the offset into the "Data" file where you will find
this frame.
"Rqs" will show you how often this frame has been requested, this will
currently say "0". If you are, or were, running a script file then this
may say '!' to denote that it is a cache entry used by the script
interpreter.
Finally, "NOTES" will say "Current", "Current (old)", "Outdated" or
"Deleted".
"Current" will be used for anything up to your configured time-out, or
twelve hours, whichever is sooner.
"Current (old)" is used between twelve hours and your configured time
out to show the frame is still being treated as current, but it is
getting old.
"Outdated" is used after your configured time-out.
"Deleted" is used when an old frame is replaced.
You may also see "No expiry (#)" if you have disabled the time-outs,
the # being the number of hours old the page is.
Frame "000 / 00" (with a weird date) is an outdated frame marked as
'deleted', and it should say "Deleted".
Flush:
This is the last option available. It will cause the Index and Data
files to be blanked, effectively erasing the cache. You should do this
if the cache grows too large. The exact definition of 'too large'
depends upon the speed of your computer and how long you are prepared to
wait for the cache to be searched, but I would suggest that if the index
shows more than 1000 entries (in total), or over half of them are no
longer current, you should flush the cache.
Sometimes you may see cache entries with a date such as "1st January 1900".
These are 'deleted' frames, which have been deleted by the script
interpreter. You can still view them.
The cache is automatically compacted, and outdated/deleted frames removed,
every time you run the program. Thus, it is only rarely that you are likely
to need to flush the cache.
REMEMBER: HOLD DOWN SHIFT AND CLICK THE ICONBAR ICON TO LOAD THE CACHE LIST
WINDOW. You can double-click on ANY valid frame shown, even
expired frames, to show them in the viewer.
Preferred pages
---------------
This stores your preferred pages. I won't say any more as it is pretty
simple really.
I've tested it with 32768 entries (and a harddisc, of course!). :-)
Online help
-----------
From the iconbar menu is a help option. This will open the teletext browser
with page 000 loaded. Pages below 100 are not valid on teletext, so this
software uses them to implement a built-in guide.
Network issues
--------------
!Teletext is quite an old application. Thus, it originally stored its
configuration, data, and cache internally. Indeed, it is still set to do
just this.
However this is not of much help if !Teletext is being shared from a
read-only applications server, be it Level4 or something else.
As of version 1.27, the location of the cache, data, and configuration
files are controlled by system variables. By default, the "netsetup"
application looks to see if Teletext is being run from Econet or ShareFS.
If so, then the values will be set up as follows:
What Variable Where
====== ================== ==============================================
Cache <Teletext$Cache> Directory "Teletext.Cache" within !Scrap.
Pages <Teletext$Pages> Directory "Teletext.Pages" within !Scrap.
Temp <Teletext$Temp> Directory "Teletext" within !Scrap.
Config <Teletext$Config> File "Teletext.Configure" within <Choices$Dir>
Otherwise, the older setup style is retained:
What Variable Where
====== ================== ============================================
Cache <Teletext$Cache> Directory "Cache" within !Teletext.
Pages <Teletext$Pages> Directory "Pages" within !Teletext.
Temp <Teletext$Temp> Within !Teletext.
Config <Teletext$Config> File "Resources.Configure" within !Teletext.
An alternative you might prefer for use stand-alone is to hardwire the
settings to those used for the networking option - ie storing things in
!Scrap and the settings in Choices.
To do this, open both !Boot and !Run within !Teletext, and remove:
%WimpSlot -min 8K -max 8K
%Run <Teletext$Dir>.netsetup
Replace with:
%CDir <Wimp$ScrapDir>.Teletext
%CDir <Wimp$ScrapDir>.Teletext.Cache
%CDir <Wimp$ScrapDir>.Teletext.Pages
%CDir <Choices$Dir>.Teletext
%Set Teletext$Cache <Wimp$ScrapDir>.Teletext.Cache
%Set Teletext$Pages <Wimp$ScrapDir>.Teletext.Pages
%Set Teletext$Temp <Wimp$ScrapDir>.Teletext
%Set Teletext$Config <Choices$Dir>.Teletext.Configure
The Utilities
-------------
gc_conv
If you have tuned your Ground Control teletext system, why go through
all that bother to retune !Teletext? Simply make sure both the Ground
Control software and the !Teletext have been seen by the filer (but not
running).
Then run this software and it will create a basic configuration file for
you.
getframes
This provides a procedure and a wrapper for it. The procedure fetches
all the frames of the specified page, and exits when it has done so.
By default, it is set up to fetch all of the "Movies at 9 on Channel 5"
information. You are supposed to run it in a taskwindow (when you will
not be using !Teletext, obviously) and let it get on with it in the
background.
You will need to have a rudimentary knowledge of BASIC in order to use
this utility. It is supplied in plain source form. Hack away!
pageview
This is an off-line teletext frame viewer (dedicated to Emlyn Owen).
Upon loading, it will try to catalogue the contents of the !Teletext
frames directory ("<Teletext$Dir>.Pages" - where frames are stored if
you clicked Okay to save. It will ask you to enter a filename. Once you
have done so, the screen will change to MODE 7 (the teletext mode) and
the frame will be displayed for you. Press SPACE to exit.
unlock
This will unlock a previously locked configuration file. If you keep the
configuration locked, hide this program.
If you are in a school environment, and you are worried about smarter
pupils downloading the !Teletext distribution for the unlocking program,
the easiest way to protect your configuration is to set it to be locked
(thus, !Teletext will not attempt to update the settings when quit) and
then simply share or serve the Configure file as read only.
So what's so good about Teletext?
---------------------------------
Teletext is free, simple and up-to-date (well, mostly). It is broadcast in
the vbi lines of your television signal. Play with the vertical hold on
your television. You'll see it there, a few lines of blinking and flashing
dots above your normal TV picture.
These frames contain up-to-date news, TV guides, chat and lots of
advertising (if you think ITV/C4 have a lot of advertising, you obviously
haven't seen Sky Text!!!). BBC2 has a good range of information on shares
and sports.
By default, Teletext offers frames 100 to 999 broken into several
magazines.
Not all magazines are used.
However, some channels use additional magazine frames, in the hexadecimal
frame number range. One example was Bamboozle on Channel 4 (are they still
doing it?). Another example is the hidden Reuters stuff on CNN.
There are even a few test frames - keep your eye on the header line as it
scans through every frame and see if there are any that seem out of
sequence. Some broadcasters seem to like "7FF".
For whatever reason, these frames aren't supposed to be directly
accessible with a TV keypad (except via FastText).
Tough. :-)
The shameless grovel
--------------------
Like anybody, I would appreciate something in return for coding this...
Maybe a meeting with Alyson Hannigan... Or Samantha Mathis... Or...
Failing that, if you have any esoteric 'Archie' hardware that you no longer
have a need for (old co-processors, mono scanners, digitisers, I/O podules,
and the like). Or, if you have one of the earlier digital cameras (ie, the
lower resolution type that plug into a standard serial port)...
Money is good too... Uh, on second thoughts (after looking at the currency
info on teletext), probably not. Should I invest in Euros? Maybe I should
buy Lira [*]. It makes it seem like you have so much more money. Can you
imagine selling the "Would You Like To Be A Millionaire" [TM] format to
them? And when they win you give them a hundred quid. :-)
Gold.
Solid lumps of Gold. Nobody can argue with the real deal. Metal has value,
don't you think? So maybe if you could send me some Gold? Failing that, a
metric tonne of pre-stressed steel RSJs? A few aluminium drinks cans? A
lousy ring-pull?
Aw, c'mon! :-)
[*] This comment was written pre-Euro, but left in as I found it amusing.
Glossary
--------
0 to F
See hexadecimal.
ASCII
"American Standard Code for Information Interchange". It's a techie
acronym that means basically a "text file".
Bamboozle
A general knowledge game "for fun" on Channel 4. It uses FastText so you
can't cheat (normally!).
CNN (properly "CNNI" for the service received on Astra)
Central News Network International. Ted Turner's news channel for "the
rest of the world". Interesting in that the 'live' Larry King show and
other good stuff appears in the middle of the night, due to time
differences. They pride themselves on impartiality and balanced reporting,
while managing to be about as biased as possible without the whole
hand-on-heart "I pledge allegiance to the southern hick gunslinger"...
Defrost
My slang for un-Freeze.
FastText
On some televisions, the FastText frames are cached for instant access.
However more often than not, the FastText system is just used as a series
of hotlinks to other magazines and frames of interest.
It is not possible to instantly cache FastText frames for you, as the
receivers that do that contain sufficient memory/hardware/software to
support the fetching of several frames at one time.
Frame
A teletext "page". Usually used to mean a "page" as seen on the screen,
but proper use refers to any and all sub-frames.
Hexadecimal (sometimes spelled "hexidecimal")
A different number system used by computer programmers due to it's
closeness to the binary system used internally by the computer.
In base 10 (what we all learn to count in school), you have the numbers 1
to 9 which represent the numbers 1 to 9. This is repeated up the scale of
things, 10 is ten 1s, and 100 is ten 10s or a hundred 1s.
Hexadecimal uses the numbers 1 to F to represent 1 to 15. There is no
'11' number, so we begin to use letters of the alphabet. So, far example:
Denary 10 Hex A Denary 7 Hex 7
Denary 22 Hex 16 Denary 16 Hex 10
Hexadecimal is just like denary with the exception that you are dealing
with units that can take one of 16 values instead of 10.
If you were interested, each hexadecimal digit translates directly into 4
bits in binary.
Level 1
The basic specification for teletext. Level 2 is available, but not
supported by many televisions and receivers. When TV goes digital, all
this will be junked in favour of a much more modern system with fancy
graphics, that is nowhere near as computer-friendly and half as fast (!).
Level 2
The next level for teletext. This allows more colours and better graphics
whilst being compatible with Level 1.
Take a look at some of the BBC 2 magazine indexes with !Teletext (or a
teletext TV), and then watch the rolling teletext presentation they show
in the off-hours. Notice a difference in the little graphic thingies?
Level 4
This is the advanced level for teletext, with fonts and vector-graphics.
You may have seen this in action in train stations on the train
information monitors.
Magazine
A group of 255 frames (x00 to xFF). All the frames beginning with 1 are
in the first magazine, frames beginning 2 are in the second and so on and
so forth.
Magazine 0 is not used, and magazines 10 to 15 are rarely used.
MODE 7
When the BBC micro was released, it had an SAA5050 chip inside it which
provided the well-known teletext character set. This has been followed
through on the RISC OS computer by an emulated MODE 7 (the ARM processor
is powerful enough to do it all by itself!).
In fact, all Acorn computers except the Electron (and early machines like
the Atom, though I believe it was available for both as an extra) provide
a MODE 7.
MovieMax
The channel formerly known as "Sky Movies", uh, or was it "The Movie
Channel"? Why can't they leave things alone!
Still, it has been MovieMax for a couple of years now. Will it change, or
d'you think they are happy with the name?
Of course, this is now only relevant if you have SkyDigital and a valid
Sky card...
MSS200
My Pace satellite receiver. Not top of the range in its time, certainly
an old heap compared to modern boxes, but gets the job done perfectly
well.
Above and beyond this you got the sexy bits (front-panel display and Dolby
Surround) at a less-than-sexy price. Ah well...
A couple of pounds for a SkyDigital box doesn't seem bad, does it?
Shame I can't apply.
Read the "Version" notes if you want to know exactly what I think of Sky,
and why I'd be tempted to turn them down if they OFFERED me the equipment
and channels, free, for a year.
PDC
Programme Delivery Control. A new idea where teletext controls your video
recorder. If you want to record an episode of "Buffy the Vampire Slayer"
you don't need to worry about recording something else because some lame
sport event (like the WorldCup) messed up the schedules. PDC will tell
your video recorder to start and stop at the correct times. The facility
also exists to pause your video recorder during the advert breaks - but
that is unlikely to appear on commercial stations as it would switch off
your VCR during the advertisements - bearing in mind that the commercial
station's main revenue is from advertising! :-)
RAMsave
When you drag a sprite from !Paint directly into !Draw (without saving to
disc first), you are using the RAMsave system. !Teletext does not support
RAMsave yet. I'll have to wade through yet more of the PRMs to suss it
all out.
Sky
The blue/grey/black stuff that is floating peacefully (and sometimes not
so peacefully) over your head. Sometimes it heats you up, sometimes it
gets you wet. Sometimes it just sits there and does absolutely nothing
interesting.
Sky
Alternatively, Rupert Murdoch's excuse for a broadcasting company that
charges viewers a lot of money to watch imported American rubbish (okay,
Buffy rocks, but can you find one single excuse for "Saved by the bell"?),
and even more dire home-grown rubbish; all provided to you thanks to a
satellite dish, and a fancy decoder.
Sub-frame (subframe)
A single "screen" within a frame. The word "frame" is often used to refer
to a subframe in much the same way "directory" is used to refer to a
sub-directory.
TeleSoftware
In the old days, when I were a lad (and all that), BBC2 used to broadcast
computer programs over teletext in an excruciatingly tragic and dire
method known as telesoftware. It was a good laugh though, but sadly it is
now a little bit of history. As computer programs require big chunks of
memory - it is unlikely Telesoftware will make a come-back.
Teletext
What all this is about. If you still don't know what Teletext is, might I
suggest you make a nice mug of hot chocolate and curl up in bed with a
nice book?
You could read "Virtual Light" by William Gibson, and pretend you have
the faintest glimmer of a clue... :^)
UHF
Ultra-High Frequency, the band television signals are broadcast on.
In the United Kingdom, this is allocated as follows:
Channel 21 (band IV) has the vision at 471.25MHz (audio offset +6MHz).
Channel 68 (band V) has the vision at 847.25MHz (audio offset +6MHz).
Bands 35, 36, 37 and 38 (583.25MHz to 613.25MHz) were unallocated for
VCRs, satellite receivers and home computers, but it seems that the
wonderful government (we're not worthy etc) has allocated channel 35
(583.25MHz) for Channel 5 in some parts of the UK. Oh fun!
Note that if you buy a PAL compatible television in Europe, there is a
good chance it will not work properly with your English satellite decoder
or English video deck.
This is because English equipment is PAL-I, with the audio at +6MHz.
European PAL equipment is PAL-B with the audio at +6.5MHz. I believe in
Australia they use PAL-G with the audio at +5.5MHz.
THIS DOES NOT AFFECT YOUR ACTUAL VIDEO CASSETTES. Please stop asking me
that! The audio on a video is recorded in digital PCM (hi-fi sound) or on
one or two linear tracks (like a tape player, but slower and narrower
which is why it sounds so crappy). The audio is just plain audio. The
PAL offset stuff happens when the video and audio are modulated for output
to the television, not before.
For better quality, and compatibility, rig up some SCART leads. Most good
videos have a video in and out, and audio in and out. Sadly, many of the
cheaper British VCRs only have one SCART socket. However I would recommend
you get to know SCART and learn how to make your own leads, as it is
highly unlikely you'll be able to buy "the perfect lead" for your setup.
I've made all my own leads thus far, and it's quite a flexible system
when you "roll it yourself".
Writable icon
An icon you can enter text into. Load !Edit, click on its icon then press
F3. The caret is now in a writable icon...
vbi
Vertical Blanking Interval. Space left at the top of the television
picture to give your television scanning circuitry time to swing from the
bottom of the picture back up to the top again. In here is inserted all
sorts of weird stuff like closed captioning, channel identification and
teletext. You can see it by playing with the vertical hold control on
your television. Lots of whizz-bang bits inside your decoder convert that
meaningless mess of dots into the teletext frames you see.
Known bugs
----------
This lists the 'issues' that are known about in this release of !Teletext.
1. Clock check does not recognise time rollover; 12:03:01 is not seen as
being only two seconds different from 12:02:59.
This is not a severe problem, it simply means you may get an extra
prompt if checking the time with messages. In non-message checking,
the clock will be updated as this will be seen to be a mismatch
between computer time and 'real' time. However, the update will set
the correct time, so this is not a problem.
This will be fixed in a future version of !Teletext.
2. If you are viewing a frame with 'flashing' text, and you then run a
script... when the script terminates and the viewer window is
re-opened, you may see a 'flash' alternate between the frame you were
previously viewing, and the last frame loaded by the script. This will
correct itself when the next frame refresh arrives, and is caused
simply because the script uses the 'current frame area' as it's
buffer.
As this is a minor thing, it'll be corrected in a future version of
!Teletext ... probably by either reloading the previous frame from the
cache (thus causing a 'flash' update), or by simply turning the flash
flag off. The former is nicer... :-)
3. Adjust-clicking the menu does not keep the menu open. Oops.
4. Reports "The save operation could not be performed (blah)" if the
<Teletext$Pages> directory does not exist. While not strictly a 'bug',
it'd be nice if !Teletext would auto-create this directory, if it did
not exist.
5. Double-clicking a file when !Teletext has been 'seen' but is not
loaded will cause !Teletext to load. That is correct. The clicked file
will not be loaded into !Teletext. That is NOT correct, it should...
6. Dragsave does not work. The core of !Teletext was written long before
I even knew about dragsaves. This will, eventually, be added in to
!Teletext. For now, it is suggested that you save to disc and then
load the file into the destination software, even if it's just a small
RAMdisc...
There may be other problems that I have not encountered. If you discover
such a problem, please send me a letter describing the problem.
Please, though, try to narrow the problem down. Was !Teletext the only
thing running? (you can discount the RISC OS apps, like !Edit and !Alarm..)
Is the problem repeatable? If so, please describe EXACTLY what steps are
required to make the problem occur. If this is your first letter to me, or
if you are using a different computer, please also describe your system so
I know what it is running.
File formats
------------
Page data:
!Teletext saved frame, filetype amp;112.
Files are 1080 bytes, laid out as follows...
Bytes 0 to 1039 are split into 26 rows of 40 characters. Row 0 is the
header. The page information is on rows 1 to 24, and row 25 is used by
pages with FastText links.
The data is not normally human-readable, you should OR each byte with
amp;80 before use.
There is no end-of-line terminator. Each line is padded with spaces
until the start of the next line.
Following the page display are a series of words:
+1040 Frame address of FastText green page
+1044 Frame address of FastText red page
+1048 Frame address of FastText yellow page
+1052 Frame address of FastText cyan page
+1056 Frame address of magazine index page
+1060 Frame address of index local to the currently selected page
+1064 Unused
+1068 Page CRC
+1072 Frame and subframe address of this page
+1076 Byte giving language of page
+1077 Byte giving language of header
+1078 Unused byte
+1079 Unused byte
The languages are:
0 English
1 French
2 Swedish
3 Czech [not supported]
4 German
5 Spanish
6 Italian
Frame addresses are in the form amp;1230004, which means
Magazine 1,
Page 23,
Subframe 4.
In normal terms, that is page 123, and the fourth one to have rolled
around.
Use (frame% >>> 16) to strip off the subframe number, and (page% << 16)
to convert a page number to a frame address.
Cache data:
The cache "Data" file is simply a collection of standard frames (as are
desribed above). Each is at an offset of 1080 bytes, and are indexed by
the...
Cache index:
This aids in keeping track of the cache entries.
It consists of a series of 20 byte entries, one for each frame in the
cache.
Byte 0 : Channel.
Bytes 1 - 4 : Frame and subframe number, in hexadecimal (0 means
frame deleted).
Byte 5 : Currently unused.
Bytes 6 - 10 : RISC OS 5-byte time value when frame written to
cache. If bytes 7-10 are zero, the page is flagged
as to be deleted).
Bytes 11 - 14 : Word showing offset into data file.
Byte 15 : The number of times this frame has been requested
(will usually say '0', but cope with other values).
Bit 7 is set by the script interpreter to mark the
frame as being one of its own.
Bytes 16 - 19 : Reserved for future expansion.
Configuration file:
The configuration file is a series of PRINT#/INPUT# values. A lot of this
could probably be better represented as a bit field. However variables
are used, and are the quickest method, so that's what has been done here.
I'm not saying it's good, just that it's practical. :-)
Repeating 9 times - channel tuning:
Channel name (string: 28 bytes (inc. terminator))
Channel tuning (integer: 21-69)
Channel fine tuning (integer: -50 to +50)
integer: not used
integer: not used
integer: not used
Repeating 6 times - no longer used, set to null values.
String, integer, integer, integer
Use Teletext palette? (integer: TRUE or FALSE)
Vertical or horizontal pane? (integer: TRUE or FALSE)
Check clock at start? (integer: TRUE or FALSE)
Clock check with no messages (integer: TRUE or FALSE)
Automatically open viewer at start? (integer: TRUE or FALSE)
Default channel at start (integer: 1-9)
Use cache? (integer: TRUE or FALSE)
Clear cache on exit? (integer: TRUE or FALSE)
Cache expiry (integer: 0-96)
Allow script execution (integer: TRUE or FALSE)
12 integers for future expansion, currently set to zero.
Configuration locked? (integer: TRUE or FALSE)
If using !Teletext from a centralised location (ie, some sort of server)
then the best way to prevent any unwanted meddling with the configuration
file is to share it read-only. When doing this, you should set the Locked
option, otherwise !Teletext will try to update the configuration when
quit.
On network servers, set the access to WR/r.
With ShareFS (Acorn Access), use the -readonly option.
Preferred pages file:
This file is a series of PRINT#/INPUT# values.
Integer: Number of entries in the file.
Repeats:
String : Entry name, up to 32 characters.
Integer: Page number, in hex. (ie, amp;101, not 101).
Integer: Channel TSDP identity, or 0 if omitted/unknown.
Integer: Channel number (1-9).
Integer: Reserved for future expansion.
Integer: Reserved for future expansion.
Transmitters
------------
Only the major transmitters for SOUTH UK are listed. There are far too many
small relay stations to list here. If you are really stuck, you should
contact your local television station. Alternatively, get !Teletext to search
for a signal, and see what comes up.
Location BBC1 BBC2 ITV Ch4 Polarisation ERP (kW)
Wales:
Blaen-Plwyf 31 27 24 21 Horizontal 100
Carmel 57 63 60 53 Horizontal 100
Llanddona 57 63 60 53 Horizontal 100
Moel-y-Parc 52 45 49 42 Horizontal 100
Presely 46 40 43 50 Horizontal 100
Wenvoe 44 51 41 47 Horizontal 500
West Country:
Beacon Hill 57 63 60 53 Horizontal 100
Caradon Hill 22 28 25 32 Horizontal 500
Huntshaw Cross 55 62 59 65 Horizontal 100
Mendip 58 64 61 54 Horizontal 500
Redruth 51 44 41 47 Horizontal 100
Stockland Hill 33 26 23 29 Horizontal 250
South-Central:
Bluebell Hill 40 46 43 65 Horizontal 30
Crystal Palace 26 33 23 30 Horizontal 1000
Dover 50 56 66 53 Horizontal 100
Hannington œ 39 45 42 66 Horizontal 250
Heathfield 49 52 64 67 Horizontal 100
Midhurst 61 55 58 68 Horizontal 100
Oxford 57 63 60 53 Horizontal 500
Rowbridge 31 24 27 21 Horizontal 500
East of England:
Sandy Heath 31 27 24 21 Horizontal 1000
Sudbury 51 44 41 47 Horizontal 250
Tacolneston 62 55 59 65 Horizontal 250
œ This is the transmitter that serves me, so this is to what the default
settings are applied.
Some less-boring legalish things
--------------------------------
The contents of this package are a proprietary product of Richard Murray.
The exceptions are the "Teletext" module, which is a proprietary product of
Colin Granville and has been supplied here with permission, and the high
resolution sprites which were designed by Roger King and are supplied with
permission.
All the software and support resources are protected by relevant national
and international copyright law.
Previously I stated that you cannot disassemble or modify the code except
where permitted by law.
But look, provided you don't pass modified versions on to anybody else, and
provided you don't amend the copyright lines and make like you wrote this
program, I can't say that I actually CARE if you hack this program.
Just do me a favour, if you do anything interesting to it, please send me
the modifications.
Alternatively, if you do anything interesting with it (like modify it to
work aboard a yacht on a laptop machine), please email me and tell me. I
like to know how my software is being used.
There is no registration fee for the use of this software. I tried that
once (different software) and one person liked the software so much he
paid twice. I won't mention how many times the logs indicate it had been
downloaded...
Naturally, I would like something back for my efforts. !Teletext is quite a
complex program, and has taken a lot of effort to develop and test. Please
reward this effort in some way. Even though this software is distributed
for no cost, it would be really nice for someone to recognize the pain,
sweat, blood, and caffiene damage due to involved in creating software. We
won't even discuss what an application of this size does to a programmer's
mental sanity. It ain't pretty.
I'm not going to fix a price on this software. I'll leave it entirely up to
you. And as mentioned in the above section on shameless grovel, I'm open to
alsorts - not just cash. I'm a geek, and a gadget freak, and I've got a
steadily growing collection of eccentric podules and other hardware. If you
have something you no longer make use of, email me. If I'm taken by it,
I'll even offer to pay postage!
In no event will I (Richard Murray) be liable for damages, including any
loss of profits, lost savings, or other incidental or consequential damages
arising out of your use or inability to use this program, even if I have
been forewarned of the possibility of such loss or damage.
That's been copied pretty much verbatim from a standard 'agreement' in
another package. Is it just me, or is it really slyly saying "The user is a
dummy!"?
Anyway, no liability.
There is no warranty either, that this program shall behave itself and not
pee on the floor and chew on your favourite shoes. Of course, if it does,
then I give you permission to reprimand it and make it sit in the corner
of your harddisc until it looks like it has learnt it's lesson.
Please also report the issue to me. All copies should be fully trained when
released, and I'm keen to know of any that escape when I'm not looking.
Contacting the author
---------------------
If you have proper Internet access, you can visit my homepage:
http://www.heyrick.co.uk/
or (if you don't care about me <sob!>) you can go directly to the !Teletext
support page at:
http://www.heyrick.co.uk/software/ttx/index.html
I am no longer 'on-line', so updates will not be so regular. Also, I do not
have regular access to my email so I won't include my email address.
Until the beginning of May 2004, you can contact me at my old address:
Mr. Richard T Murray
16 Elm View
Ash
Aldershot
Hampshire
GU12 6AN
PLEASE WRITE THE ADDRESS EXACTLY AS SHOWN - ESPECIALLY THE NAME. That is
what it says on the Royal Mail International Redirection form. I'd like to
hope that they'd treat "Rick Murray" as "Richard T Murray", but I don't
want any reason for the post going astray. If it isn't redirected, I will
never receive it. Period.
Feel free to send me your comments, suggestions, even criticisms.
Also, I'm always interested in knowing how my software is being used. If
you use it for a specific purpose, or with unusual hardware (ie, a receiver
you built yourself), please tell me about it.
Also, if you prefer my !Teletext over Octopus' !Teletext+, please tell me
why. Likewise, if you tried my software and preferred what you were using
before... please tell me why.
What's your "most annoying feature"? Do you have a wishlist? Get in touch,
maybe I can do something about it.
2003-05-24 @ 20:58 CET
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Copyright © 2003 Richard Murray