Trevor Buck tunes himself into the Morley Teletext Adaptor and downloads his review

The Morley Teletext Adaptor can capture teletext information and software broadcast by the BBC (Ceefax) and ITV (Oracle) through a standard television aerial and display them on an ordinary TV set. The advantage over teletext by phone is that, once you've bought the hardware, the software comes free and there is no subscription charge.

Acorn already has a device to do just this which I have used for some time, but it costs £149 and is unable to take advantage of changes being made to teletext broadcasting - which the Morley device can. The newer adaptor comes with ROM chip software and manual just like the Acorn one, but goes about its task in a very different way.

The instructions to install the ROM are clear and I had the whole thing put back together and all plugged-in under three minutes. Unlike the Acorn system, which uses the 1MHz bus and creates an alternative filing system, the Morley unit plugs into the user port and works from within the current filing system.

Now if, like me, you try out new goodies by giving what seem to be logical commands, and seeing how far you can get before you have to resort to the manual, this adaptor is for you.

I was unsure how well I would get on at first, as there is a message to remind you that the system has not been fed with its required TV channel data on power up. Not to be outdone I went ahead with *TTEXT and was rewarded with the working page tuned in to BBC1 Ceefax. The people at Morley have built-in a set of default channel data while the unit is under development, and this just happened to be the same as those channels for my area.

In order to tune the unit in all you have to do is type *TUNE and a Basic program is run to tune the unit to the channels. Full instructions on how to use it for fine tuning are given in the manual, and it took me less than three minutes to find all four channels. All the controls are on the keyboard.

The channel tuning data is saved onto disc in a file called 'channel' and reloaded by the command *CHANNEL. Every time you turn on you can run a !BOOT file to do CHANNEL and TTEXT for you.

The unit tunes into the default page of 100 on BBC1, and the teletext page is displayed by pressing Tab. Escape takes you back to the working page. The on-screen menu gives you the options to save a screen to disc, catalogue software, download software, toggle reveal on/off, toggle hold on/off, and select a new channel (1-4). They are entered by a single key press, with no need to press Return or select an option via the function keys.

Like a TV set with teletext, all you do is key in the three digit number of the page you want, and wait for it to be broadcast. You can select a new page from either the working page or the current page displayed.

Using the 'N' key prompts for the channel in the bottom right box on the working page, and you must type in a number from 1 to 4. The 'page header' information changes to show that you are now on the desired channel.

Reveal and Hold have their current status displayed on the working pages, and when used with a displayed page their on/off status is flashed up at the bottom of the screen.

To save a screen to disc is simple - just select the page number you want and press 'S'. The system prompts for a filename and then saves the screen to disc. These screen images can then be *LOADed as and when required.

However, for most people the main attraction will be accessing the software. Pressing the 'C' key puts the unit into display mode for BBC1, page 701, where *CAT is found (a list of the current software available).

The Download command also accesses page 701 and includes an extra line prompting for the page number of the program you want to download. Each page is stored so as to form a complete program, and you are given a choice of saving this to disc, or running it in Basic.

The unit comes with full error checking, and when errors occur it will try to correct these on the next transmission of the block. At the time of writing, the blocks change every 20 seconds or so, and the unit will keep going until it has downloaded the software or you give up.

One of its nice touches is that, instead of just 'Searching...' over and over again, it gives the name of the program, how many blocks long it is and the number of each block as it is downloaded. This is initially in white and changes to green when complete. If there are any errors they are indicated and corrected on subsequent passes through the blocks.

The majority of the commands in the ROM are those used to access teletext from within a Basic program. The command set has been dessigned to that all transmitted software that uses 'live' teletext data can be used with the Morley unit. This has had to be done as the BBC transmits programs designed for use with the Acorn unit only, so that some 'dummy' commands are included to get round the 'Bad command' error. The one thing that will have to be taken out of some programs is the test for the value of PAGE, as this is used to check that the Acorn adaptor is receiving teletext.

When downloading software, there is no real difference between the Morley or Acorn adaptors in the time it takes to go from block to block, as this is governed by the speed at which the broadcaster sends out the sequence of sub-pages that make up each file.

The time saving is that the Morley adaptor saves the files to disc at the press of the space bar, and ASCII files can be downloaded just as readily as tokenised ones. The Acorn unit leaves the program in memory, and a change of filing system is required before saving can take place (sometimes after first having to find out information from other Ceefax pages).

Where the Morley unit will succeed over the Acorn one is that it can receive 8-bit data transmissions, and not just on the existing, limited number of data lines but over all 625 lines of the TV signal. Thus, if cable TV takes off, we could see a whole channel being used for data - and pages being accessed almost as quickly as the number is entered.

In terms of price, performance, future expansion possibilities and those little touches that show thought for the end user, I would recommend the Morley unit.

Morley Teletext Adaptor, £90.40 inc (£100.35 with pin), BBC B/B+ (Electron version under development)