The wealth of add-ons available for the Acorn Electron never ceases to amaze me. From the piddling little First Byte Printer Interface to the huge mind-blowing Hybrid Music 5000, there seems to have been a third party supplier willing to work on gadgets for each of every one of the Elk's expansion ports. Now, after several years of bidding and being outbid on eBay, we've landed yet another biege-coloured hardware interface: Millsgrade Ltd's Voxbox.

Voxbox is a 'Speech Synthesis System', a chunky looking box originally released very early in the Electron's life and which plugs onto the rear expansion port of the Electron. It comes with its own instruction manual of eight pages and a cassette featuring two programs that teach you how to use it. Now perhaps I am a cynic, or perhaps I've heard that awful sample in Exile (which is meant to speak "Welcome to the land of the Exile" but just sounds like garbled nonsense) one time too many, but my hopes for this interface were not high. As such, I got something of a shock when, about a minute into the loading of the first example program, the Electron emitted a fanfare and a dead-pan voice shouted, at rather a loud volume, "VOXBOX, Your Speaking Electron Computer. By Neil Ellicott!" Awesome stuff! The machine was talking to me, perfectly clearly and perfectly understandably.

The main program itself takes around three minutes to load from cassette and is fairly robust, with the BREAK key returning you to the menu screen, not resetting the machine. And, whilst the instruction manual at first glance seems to be rather complicated, a few minutes worth of experimentation with the program itself will see you listening and learning extremely quickly about the methods Voxbox uses to create recognisable speech.

Put simply, a large variety of sounds (allophones) are stored in the ROM memory of the Voxbox expansion. You simply learn these sounds, and string them together, to create the words you want. The first program presents you, after its introduction screen, with an 'Edit Screen' divided into three sections. The top section lists all the allophones available, which you can step through with the cursor keys and move to the second section with the COPY key. You can then 'say' the string of allophones in the second section by pressing the "S" key. When you do this, you get a rather rudimentary graphic of a mouth in Mode 5 opening and closing to boot!

Finally, you can create your own 'catalogues' of words based on those you create with the allophones. The default catalogue contains roughly three or four words beginning with each letter of the alphabet. However, you may add and delete words as you wish, presumably until the Elk's memory is full. As an example, the User Guide suggests you create the word 'computer' with the allophones KK1, AX, MM, PP, YY1, UW1, TT2, ER1. You can save this combination of allophones by pressing the M key and typing in 'COMPUTER'. It is then stored in the 'catalogue array' in memory, with whatever other words that begin with C are held there. The whole catalogue can be saved to tape by pressing T.

The program itself is incredibly user-friendly, with the majority of the allophone information detailed in the User Guide, also stored within the program in text format. So, for example, because, in the English language, the sound of a letter changes depending on where it appears in the word, you can move the allophone cursor to the allophone you think it may be, and double-check by pressing the D key to bring out the information about that allophone. For example, DD2 is the 'd' sound that begins words ("Drain"), DD1 is the 'd' sound that ends them ("End"). Instead of cross-referring to the manual the whole time to find out this information, pressing D brings it up on screen instantaneously.

With this ease of use, it is no longer than around half an hour before you begin to create recognisable words with the Voxbox. However, as you will probably appreciate, a certain amount of 'work' does have to go into discovering how a word should be written using this first allophone program. The much better program is that recorded on the flipside of the cassette.

This second program simply raises PAGE to &1500 and allows you to use four new commands in your BASIC programs. So, you can enter a line such as:

   10 A$="WH,EH,PA2,EL,KK2,UH,MM,PA3,TT2,UW2,PA3,TH,UH,PA3,KK2,LL,AE,SS,SS,IH,KK3,
PA5,GG3,EY,MM,NG,PA3,EH,KK2,SS,PP,OW,PA3,TT2,UW2,PA3,TH,AW,SS,AE,NN1,DD1,PA3,NN1,P
A3,FF,AY,VV"

and the Elk will say "Welcome to the Classic Gaming Expo 2005". It doesn't take a genius to see that this could be utilised in educational programs to have 'live' speech as a part of play. To save the new program, you use a new command SSAVE <filename>.

So far it's all very impressive stuff. However, as with most Electron addons, there are a certain number of drawbacks. The first, and most irritating one to a modern user, is that Voxbox will only work from cassette. This is simply because the addon was produced before Acorn produced the Acorn Plus 1 interface. When this is connected, of course, the edge connector is no longer available for the Voxbox to be connected to. With some clever coding, it is possible for the Voxbox to function on ADFS disc, connected to the rear of the L-shaped Acorn Plus 3. Without a total rewrite of both programs though, saving new programs incorporating Voxbox code would have to be done to tape. The whole process therefore of creating disc-based Voxbox games will be fiddly and frustrating.

The second drawback is that Voxbox will only really work in Modes 4, 5 and 6. In other Modes, whenever it 'speaks', it causes the screen to fill with snow.

The third, and final, drawback is that, assuming you're stuck on tape with PAGE raised to &1500, any budding programmer wishing to use the Voxbox system in these modes is going to be limited to a very small amount of memory to work with. One wonders just what type of BASIC games would even be possible - machine code seems to be the only answer, but only BASIC commands are given for controlling the Voxbox.

Having said all that, I am working with a new Public Domain software house, The Organ Grinder's Monkey, on a new disc-based game utilising the Voxbox - so it may be that these limitations can be overcome and something decent written to impress people at next year's Classic Gaming Expo. Watch this space.