Access to a wide range of bulletin boards and Prestel-type systems is easy with Specnet, says Tony Dennis

New software for the VTX5000 means Sinclair owners can access bulletin boards, electronic mail services, databases and even The Source.

Before Prism's demise, the VTX5000 had already dropped from £99.95 to £70. When Prism's old stock comes onto the market, the VTX will probably be one of the cheapest modems yet. The drawback to a VTX5000 was that it could be used only for accessing Prestel services (Micronet/Homelink) or systems that had adopted the Prestel format (ICL Bulletin and Communitel). That has all changed: new "scrolling" software allows it to be used for accessing systems which don't use pages to display information but scroll text continuously across the screen. Bulletin boards are a prime example of a "scrolling" system.

In fact, one new package, Specnet, was designed specifically to allow VTX owners to access the growing number of bulletin boards which support 1200/75 baud rates. The program is a modified version of Andrew Glaister's Specterm which turns any Spectrum into an intelligent terminal for telephone communications use. Specterm was published in Sinclair Answers but Stephen Adams' version for the VTX never appeared. He is now selling Specnet himself.

The most interesting feature is the facility to download or upload files, be they Basic, machine code or text. This is possible through the use of error checking protocols. The protocols go under various names - Xmodem, Christensen, blocksum or CP/M - but they all amount to the same thing.

A number of Specnet features are available when you go into EDIT mode. A good example is the ability to stop what you type on the keyboard being sent to the screen (EDIT + N). When you want to see what you are typing again, just press EDIT (SHIFT + 1) and E to make the screen echo the keyboard input. These commands are contained in the instructions, but I found things were self-explanatory, except when it came to file transfer.

Xmodem protocols require certain communication settings. These are: one start bit, eight data bits, no parity and one stop bit. All UK bulletin boards currently support this protocol, so Specnet defaults to this setting. However, there is another common setting used by BT Gold, among others. That is: one start bit, seven data bits, even parity and one stop bit. To change Specnet, go back into Basic, POKE 26603,123 then RAND USR 26600. Specnet can then be used with BT Gold.

Going on-line with Specnet was quite straightforward. Power up the Spectrum with VTX5000 attached. Take the option (7) which returns the micro to Basic. The program is then loaded in the normal manner [LOAD ""] after which an introductory menu appears. This contains the numbers of four bulletin boards to try. Keep the modem switched to the Mnet setting and phone the required number. When the board's modem answers, flick down the line switch and the green carrier detect light should come on. The bulletin board's welcoming message should then appear on the screen, allowing you to sign on as usual. When accessing a bulletin board such as CABB London it was necessary to ask for ten nulls to see the text perfectly. Nulls are a stream of zeroes designed to give a slow terminal time to catch up. Otherwise things operated very much the same as any other terminal.

Specnet was also used to access BT Gold, the electronic mail service. First, it had to be poked to alter the settings. Then the correct phone number, Gold's 1200/75, has to be used. Once the system's modem answered, I had to flick the line switch down and send a couple of carriage returns (press Enter twice) before the familiar PAD> prompt appeared on the screen. Again, the VTX needed nulls before the text would appear perfectly, but it is easy to get BT Gold to change this or set them up when you first subscribe.

Specnet can be used to access populate on-line services in the US such as The Source or Compuserve. However, it is first necessary to subscribe to Packet Switch Stream (PSS). This is a service which allows the user to make a local call to what is known as a node. From the node it is possible to hook into data lines all over the world. The big mainframe data services are all on some form of PSS system. Naturally, this all sounds very complicated for the ordinary Spectrum user but it works out much cheaper than phoning the US direct.

Software such as Specnet cannot turn the VTX into a 300/300 baud modem. This is because baud rates are fixed in hardware. There are no supressed frequencies either, despite what some owners persist in believing.

Specnet has the facility to save programs to cassette, Microdrive and certain disk interfaces which follow Microdrive procedure. It does not allow the use of a printer on-line. Specnet's instructions are pretty primitive, and changing protocol settings requires a poke instead of a menu option.

Notwithstanding these gripes, Specnet is still ahead of its rivals.

It is unfortunate that the VTX works with only 16K, 48K and Spectrum Plusses because the RS232 interface needed to drive a modem is built in to the modem and cannot be accessed. Because Specnet is so new, only CABB carries any Spectrum software, although all the bulletin boards could.

The Xmodem method of file transfer breaks data down into blocks. If any corruption occurs, the program detects that and asks for the defective block to be sent again. Ten retries are allowed before the whole transmission is aborted. The effect is that if the download is completed the file must be error free. Using Xmodem protocols takes a good deal longer than transferring files by other methods.

Text files where any corruption is easily spotted need not be transferred using error checking. However, Xmodem is an extremely reliable form of transferring software, which is what 90 per cent of VTX owners will want to do anyway. Incidentally, as files transferred with Xmodem protocols are held in tokenised form, it is possible to store a program for say a BBC Micro on the Spectrum, and then transfer it to the BBC Micro at a later date.

A second software package for VTX5000 owners, by Stephen Gold, is available to Prestel/Micronet subscribers for £2.95. Go to page *600614988# to download. It is scrolling software and has a menu option to allow you to select communication settings. The main difference between this and Specnet is that there is no software download facility. It can, however, be used for BT Gold and bulletin boards.