This is the support area for Teletext+ users. If you haven't already got Teletext+
then see the main
Teletext+ page too.
Teletext+ is now fully compatible with the IYONIX
pc.
Existing users can upgrade to Teletext+ v7.25 by sending a £15
cheque payable to Octopus Systems together with their master disc.
Alternatively you may send a cheque and supply your serial number and Email
address for an update by Email. Please add £5 (ie £20 total) if
your would like a wire-bound 5th edition manual too.
Note that most Teletext cards, including those from Computer Concepts, do not
have a podule ROM, so there is no need to update the card. Similarly,
external teletext adapters from Ground Control, Solidisk and Morley will not
need any updates other than the new Teletext+ software.
Teletext+ v7.25 Software
Features added recently include:
Now handles pages transmitted with incorrect checksums. Note that ITV
no longer transmit correct CRCs, so this update is important for data logging from ITV (see below)
Grabs share price data from Channel 4 with their new transmission system
Alarms now work for programmes starting after midnight
Alarm window shows channel for TV and Radio programmes
Alarms can be set if keywords appear in programme description (not just title line)
TeleButler (TV output) display now shows the channel for TV and Radio programmes
Improved TeleButler display on televisions (less flicker)
Several script improvements
Fully compatible with RISC OS 4 and RISC OS 5
Problems with ITV Teletext
We have been in contact with Teletext Ltd to discuss the problems
with Teletext broadcasts on ITV. They have just upgraded their Teletext
insertion systems and have experienced a number of problems with their new
software.
Initially the new system was sending pages with incorrect sub-page
numbers, so a page with a single sub-page was being sent with sub-page
number 1 instead of 0, and some other pages were sent with missing
sub-pages (eg sub-pages 1, 2, 3, 29 and 30). This problem has been fixed
in their latest firmware and the London transmitter is being upgaded
today (2nd June). Other transmitters across the country should be
upgraded soon.
This problem will cause Teletext+ to stick when it encounters a single
sub-page with a sub-page number of 1. This implies that there should be
more pages so Teletext+ will wait without moving on to the next page.
Teletext+ will timeout if it doesn't receive a page within a set time, but
in this case it will still receive the page and it won't timeout.
As a temporary solution you can remove any pages from your cache and
scores file that suffer from this problem (ie any pages with a single
sub-page numbered sub-page 1 that Teletext+ sticks on). Otherwise you will
have to wait until Teletext Ltd upgrade your transmitter.
A more serious problem is the lack of CRCs checksums on their new system:
Corrupt Pages on ITV Teletext
Every Teletext page should be transmitted with a CRC (Cyclic Redundancy
Check) checksum which enables the Teletext decoder to determine whether the
page was received correctly.
The new hardware that Teletext Ltd have installed does not broadcast
a CRC check at all as the manufacturers did not regard it as important.
This violates the Teletext specification and is likely to cause problems
especially for anybody who wishes to log data from ITV. It is unknown
whether this is likely to be resolved, but if you would like to make your
feelings known you can contact them on:
Broadcast Support Teletext Limited 101 Farm Lane London SW6 1QJ
Fax: 0171 386 5618
When Teletext+ receives a page with an invalid CRC checksum it flashes an
asterisk in the page header to indicate a fault, even though the page may
be correct. ITV Teletext are sending pages with a CRC of 2020 for every
page. This is a violation of the Teletext specification and it makes it
impossible to determine whether a page has been received correctly.
This shouldn't affect Teletext+ users too much unless you have script
commands to log data from an ITV page. In this case Teletext+ will wait
until the page is received with a good CRC before moving on to the next
page.
Teletext Ltd say they
are investigating the problem and hope to resolve it soon. Meanwhile,
we have produced a new version of Teletext+ (v7.09) which ignores the
CRC if it is 2020. Just install the new version and the problem should
be solved. For more technical details, read on:
More About CRCs
This section explains more about CRCs for users who want the full technical
details - you don't need to read it to use v7.09. Some users have suggested
that Teletext+ shouldn't stick on a page when the CRC is incorrect. In
fact it will display and cache pages with a bad CRC just like pages with
a good CRC, with the proviso that it will never overwrite an old cached
page that has a good CRC with a newly received page that has a bad CRC
(ie if you return to a page that has previously been received it will
always show a good entry in preference to a newer version with a bad CRC).
Once all of the sub-pages are received it will move onto the next page
that it wants to cache. However, if a script command is used to log data
from a page then Teletext+ will wait until a good copy of the page has
been received.
If you are logging data from ITV then Teletext+ must be fooled into thinking
that the pages have good CRCs when in fact they don't. This is achieved
in v7.09 by telling it to ignore particular CRC values and treat the page
as good when they are encountered. The CRC values to ignore are set in
the Teletext+ !Run file:
Set TTX$ignoreCRC 2020 8080
This line makes Teletext+ ignore the CRC if it is 2020 or 8080
(hexadecimal).
A CRC error is indicated in the status window with a "BAD CRC" message when
the page is received and the CRC also appears here. The cache list also
shows bad CRCs by marking the page with an asterisk.
If another channel is posing a similar problem and showing BAD CRC on every
page then you can identify the CRC value that is being sent and enter
the same value in the TTX$ignore line.
Alternatively, if you have very poor reception and receive a lot of CRC errors you can make Teletext+ ignore the CRC check completely by changing the line in the !Run file to:
Set TTX$ignoreCRC *
This may also be useful in countries where CRCs are not transmitted.
TeleButler Home Information System
It is now possible to connect your Acorn computer to all of the TV sets in
your house to provide a useful home information system.
All incoming and outgoing telephone calls can be displayed on every TV set
in your home, so when the phone rings you can switch to channel 9 and
see who is trying to call you.
This is possible using a Computer Concepts tuner/teletext card which has an
RGB/composite video output in addition to the normal Teletext functions.
Our Caller Display and Teletext+ software work together with this card
to make it display useful information which can be connected to your TV
sets.
The display is quite separate to the computer's normal display, and the computer
can still be used normally while it is generating the extra TV display.
The TV display can be used to show all sorts of useful information and
there are even system calls to allow your own programs put useful information
on it.
Caller Display and Teletext+ update this display automatically, so if the telephone
rings or Teletext+ beeps to warn of a television programme starting the
details are immediately displayed on a spare television channel.
Display which can appear on channel 9 of every TV in your home
Ceefax has just started broadcasting regional pages in most areas, with local
news (page 160), weather (page 402) and travel (437). The TV pages (603
etc) also show the local ITV region. See Ceefax page 300 for a full regional
index.
Irlam Risc TV Card
The Risc TV card offers a television display on your desktop as well as Teletext.
It doesn't slow the computer down when displaying television (since the
television image is overlayed on the video output which is routed through
the card) and the window can be re-sized or made full screen. The TV sound
is played through the computer's sound system and it is also available
on a separate headphone jack. It has a composite video and S-video input
for connecting video recorders, camcorders or digital cameras.
The system can grab still frames and save them as sprites and moving
video is promised as a future upgrade. The optional Teletext module is
needed to receive Teletext which works well with Teletext+.
If you already have Teletext+ and wish to upgrade your hardware we can
supply the Risc TV card with the Teletext module for £339 (you can
even trade-in your old teletext cards or adapters). We can also supply
the Risc TV card, Teletext module and Teletext+ software for £369.
Prices include VAT and carriage.
Hints for Risc TV Users
Steve Lee passed on this useful tip for Risc TV users:
If you have a video recorder connected to the composite video you can
set the RiscTV to display the composite video input (channel 0) and then
change the channel you are watching on the video machine (ie using the
tuner in the video recorder). This allows Teletext+ to use the Risc TV
tuner so it can happily hop between the channels without affecting your
viewing. Obviously you need a video recorder to do this, but it is a very
useful tip.
Hints and Tips
Multi-Line URLs on teletext Pages
Teletext pages often contain URLs (Universal Resource Locators) which
you can click to open the relevant page (assuming you are connected to
the Internet at the time). This works for Email addresses, web pages,
ftp sites and some other Internet services. Similarly clicking on a telephone
number will dial the number. However, some web page addresses are quite
long and can extend over two lines on the Teletext page. In such cases
Teletext+ only looks at the single line so it will not open the correct
address. A simple solution is to save the Teletext page as text into Zap.
It is then possible to join the two line by deleting the intervening space
and Return character and then open the web page by Alt double clicking
over the URL.
It has been suggested that Teletext+ should automatically detect such
cases and append the next line if it looks like part of the URL.
I don't think it is possible to reliably decide whether the next line
is part of the URL so I am reluctant to do this as it may cause existing
single-line URLs to fail should there be text on the subsequent line.
Any suggestions would be welcome.
Searching Sub-titles for Keywords
You can search sub-title pages just like any other page, but if a match is
found it will generate a beep rather than appearing in the keywords window.
You can use this to search football sub-titles for the word "goal" or
"scored". You can also use it to make the computer beep when a particular
subject arises in a television programme. For example, you might hate
Top of the Pops, but want to see one particular artist, or you might be
interested in a single item that you know will appear on Watchdog or Tomorrow's
World. For example:
Teletext+ v7.08 uses three descending beeps to indicate that a keyword
match appeared on a sub-title page. Earlier versions use a single, long,
low beep.
When using this facility you must select the sub-title page on the required
channel and Teletext+ will not grab any other pages while it is grabbing
sub-titles.
TV Programme Listings
If you press REVEAL when looking at a TV listings page you'll see the date
and an extra time appear on the page. This is used for video programming
via Teletext but it can be useful to find when the last programme ends
without going to the next sub-page.
Changes to Page Numbers
Many page numbers have been changed on Ceefax and ITV Teletext, and you may
find that the page list facility no longer takes you to the right page.
Furthermore, the keyword searching system will not be much use if it is
searching the wrong pages for keywords. Since pages are normally searched
by group name it is a simple matter to update the #define section of your
script file using the new page numbers.
We have produced a new script file
(21 Jan 97) which can be downloaded and merged with your existing script
file. If you have entered your own keywords you should just replace the
#define sections in your file with the one from this new script file.
If you are using the default script file you can replace it with the new
one.
Alternatively you can edit the script manually: Shift-Click on the Teletext+
icon (on the icon bar) and then double-click on the Script file. Search
for the Radio programme listings (lines starting with 264) and change
the numbers to start with 164.
For example, the radio 4 listings were on page 2644 (ie page 644 on
BBC2), but they are now on page 1644 (page 644 on BBC1), so you should
change the line:
2644,Radio 4 Today
to:
1644,Radio 4 Today
When you have changed all of the radio lines in your script file, press
f3 and then RETURN to save the file.
Telephone Number Dialling
Many Teletext pages advertise telephone numbers and Teletext+ can dial these
numbers automatically (via DTMF tones played through the computer's loudspeaker)
when you click on them.
Teletext+ Keystrip
We now have a new Teletext+ keystrip with all of the mouse and key short-cuts
listed. Our thanks to Roger King for providing the initial design.
You can download the keystrip
from here and drag it to Spark or Sparkplug to decode it and extract the
Draw file.
Teletext on the Web
Teletext Ltd provide Teletext for ITV and Channel 4 and they now have
their own web site: http://www.teletext.co.uk/
Weekend Operation
Separate modes for weekend operation are not supported yet, although it is
possible to install two copies of Teletext+ in different directories and
use different script and score files with each one. A simple BASIC program
could even be written to run the appropriate version depending on the
day.
The Web site is particularly useful as it contains details of aerial
types, reception problems and NiCam availability. Their new telephone
number is 0345 010313 but overseas callers should use +44 181 231 9191
and this line is manned 0900-1700 on weekdays.
Teletext Specifications
More details of the Teletext system are available in the MRG
Systems Tutorial. This will be of particular interest to users writing
their own software to grab Teletext pages.
For more details please email us at
or see our contacts
page for our phone number and postal address.
