Acorn's Teletext adaptor for the BBC micro has proved less popular than hoped. Geoff Bains reports on a cheaper alternative from Morley Electronics that may be set to change all that.

When the BBC micro was first unveiled one of its many expansion capabilities was the facility to receive and display Teletext information directly from a TV aerial and to download software via the Teletext service. Within three years or so Acorn finally produced its Teletext adaptor for a price of £225.

Acorn Teletext adaptors have not sold in vast numbers even though the price has since dropped to around £148. The field has been open for an enterprising company to produce a Teletext adaptor for a more reasonable price. This is the position in which Morley Electronics hopes to find itself. The Morley Teletext adaptor can cost as little as £75, though a more reasonable system (with driving software) is around the £100 mark.

Morley's adaptor comes in a plastic half-height disc drive case - itself an advantage over the second processor sized box of Acorn's - which plugs into the User Port and the auxiliary power supply under the Beeb, and a TV aerial. If your disc drives already use the auxiliary power socket you will need Morley's power supply too, for £10. Why Morley chose to use the User Port is anyone's guess. There is already a section of the 1 MHz bus memory map set aside for Teletext so using this, and leaving the User Port free for mice and the like, would have been preferable.

1f you choose to use Morley's software (and it would be silly to buy the adaptor without it) you have a choice of either ROM-based software or a disc-based program for sideways RAM. Either way, the effect is much the same. It will allow you to display Teletext pages from any TV channel, download software, save broadcast screens to disc or cassette, and even to tell the time; all without consuming vast quantities of RAM and raising PAGE, as does Acorn's Teletext ROM.

The first job to do when you unpack your new adaptor is to tune it to the frequencies of the four TV stations in your area. This is all done electronically and automatically - a great improvement over the twiddling around the back with a screwdriver necessary with Acorn's adaptor. Once the adaptor has found the four stations, it saves the tuning information to disc or cassette for next time. You can even blow your own EPROM (or get Morley to do it for you) to have this information always to hand whenever you use the adaptor.

Now you can actually receive Teletext information. A simple menu screen allows you to select the channel, page number, and so on required and the chosen page is then displayed. Similarly you can select the downloading feature from the menu and transfer the free software broadcast with Teletext into your machine ready for running or saving.

Once a page is up on the screen you can just read it, hold it there, reveal any concealed parts, step on to linked pages with the cursor keys, or store it away on cassette or disc.

Morley's Teletext software does not end there. There are over 99 * commands available for you to make full use of the adaptor; all of which use the Beebug convention of an optional 'M' prefix to avoid command clashes. These range from convenience commands, such as *ITV2 to tune to Channel 4 and *KIDS to display the jokes pages on BBC 2, to building block commands for your own control programs, such as *TRANSFER to store a page in memory and *ROW to read a specified page row into memory, and several dozen more. There's also provision for printing the date and time as these are broadcast along with the Teletext data.

With such a plethora of commands you would be forgiven for expecting a pretty hefty manual to accompany the Morley Teletext adaptor. However, the tome that does come with the package is anything but comprehensive. It is true that a good setting-up and fault-finding section is included and each command is listed along with a (very) brief description of what it does but there is very little in-depth explanation as to what use half of these commands could be put. More importantly, even the simple introduction to using the adaptor in its simplest form - to display Teletext pages and to download software - is brief to the point of downright misleading. You really have to experiment for yourself with this package before you can get to grips with it.

All this is a great shame as the adaptor itself, although not built to the same standard, is better than Acorn's in many respects, and cheaper, and the software could not be more comprehensive.

Teletext is a free service run by the television broadcasting authorities that utilizes sections of the broadcast TV signal to transmit digital data in a standard format. Teletext data may be received by any suitable receiver and decoder connected to a normal TV aerial without any payment on the part of the receiver except for a TV licence.

Most Teletext receiver/decoders are built into TV sets (so-called 'Teletext TVs'). However, the Teletext-compatible mode 7 display of the BBC micro means that much of a Teletext receiver/decoder hardware already exists in this machine. A Teletext adaptor turns the Beeb into a Teletext-receiving terminal capable of all the functions of a Teletext TV except the super imposition of subtitles over broadcast programmes.

The Teletext information is broadcast as a series of 'pages', each being a mode 7 screenful. The information covers a wide range of subjects - travel news, share prices, weather, TV programs, recipes, jokes, etc. - and also software for the Beeb. This software similarly covers a reasonable range of subjects, though with a heavy schools bias, and is only available to owners of Teletext adaptors. Normal Teletext TVs are not able to download software.

Product: Teletext Adapter
Supplier: Morley Electronics, 1 Morley Place, Shiremoor, Tyneside, NE27 0QS. Tel: 091-262 7507
Price: £74.45 (adapter), £24.95 (ROM software), £23.95 (disc software), £9.95 (power supply)