The computer can help save the time and labour of telephone calls simply by use of a well-planned database (A&B Computing - October 1984) to produce up-to-date telephone lists of commonly dialled calls. An automatic dialler 'phone needs its own special list: mine sits, under glass, immediately beneath the instrument. Far more sophisticated aids are to be had however, particularly modems.

A modem changes computer signals into telephone signals (MODulates them) and DEModulates telephone signals back to computer signals. As telephone systems (and computers) differ, the modem has switches to match:

1. the speed at which the signals are to be transmitted and received (called the Baud Rate),
2. whether signals can go freely in both directions, called "duplex" or in only one direction, so that each operator has to switch (rather like the familiar "over to you" of radio conversations) known as "half-duplex". The kind of computer at either end,
3. the telephone system's rules for transmitting. signals (called "protocols").

Modems may be either:

1. Acoustic - you place the telephone handset in a shaped plastic cup. The computer signals are turned into sounds which enter the telephone receiver, and are then turned back into electric impulses and travel down the telephone wires. Signals from the answering computer come down the telephone wires, are turned into sounds by your telephone, then back into electricity by the modem. This is obviously longwinded and surrounding noise may spoil the signal. They are too clumsy for busy people and are not covered in this review.
2. Hard wired - these omit the intermediate sound stage. They plug direct into the telephone jack-socket and the telephone plugs into them. When the modem is not being used it is "transparent" to normal telephone calls.

Just as the modem imposes a set of rules (as to how information is to be sent) on your telephone, so software is necessary to impose rules on your computer. The disadvantage of programs on tape or disc is the need to load before telephone communication can begin. An improvement is to have the software on ROM, which can be called up by a single keyword.

This slim flat black plastic box is large enough to sit under any kind of telephone. It is excellent for communicating with PRESTEL - the huge British Telecom Database - but for "user-to-user" communication (i.e. between office and factory) it only offers "half-duplex". While this method of communication is less likely to error (because the signals travelling one way do not interfere with those moving in the opposite direction) it requires tedious switching between "transmit" and "receive". Nor can it be used at all to get access to some data bases or "bulletin boards" which operate at 300 baud (30 characters per second) "full duplex".

The cabinet is rather flimsy: looks as if it would break if dropped hard and the front control panel is confusing in that to switch "ON-LINE" you actually have to move the switch away from the word "LINE". Although the handbook makes this quite clear, good equipment design should be such that a device can be used without reference to the handbook.

The handbook states that this operator switching can be software controlled but gives no hint as to how this can be achieved. I rang PRISM to ask and was told, "Put the switch in the position midway between Tx and I tried this but found there was no such position. Perhaps PRISM could clarify this and add it to the handbook.

I was irritated that it came with no mains plug fitted, particularly as a plug with a 5 amp fuse is needed. For most people this means a special errand to buy one.

At a price of 89.95 (inc. VAT), which includes the ROM control chip, this is much the cheapest hard-wired modem available for the BBC and is perfectly adequate if the user only wants access to VIEWDATA.

This excellent menu-driven program makes:

1. entering and leaving the PRESTEL network,
2. saving and printing individual pages,
3. recalling those that have been saved,
4. "down-loading" software transmitted over the telephone lines,
5. leaving and receiving mail box messages

all become very simple.

Its limitation is that it offers no facility for businesslike user-to-user communication. An excellent feature is that the program allows full access to the computer's operating system (to read a disc catalogue, define a user key or even switch off a diary alarm) at any time.

The flimsy handbook is excellently produced, with helpful screen pictures but, alas, no index or fault-finding procedures.

A business-like box, just a little larger than the base of a standard B.T. 'phone and, thoughtfully, just large enough for my autodialler to sit comfortably on top. It is well organised: the wires disappear at the back and the (rather ugly) control panel faces the user. I have been using an acoustic modem for a year and finding it tedious and frustrating but the Nightingale certainly made me sing like a bird! It came with clear instructions and correct cables (with plugs on), took me a few minutes to install and worked perfectly first time. There is a wide range of operating modes and speeds.

The facility to transmit at 1200 baud and receive at 75 baud in full duplex operation (no "over-to-you" needed), is especially valuable for the business that sends large quantities of data in one direction. The retailer, making daily trading and stock reports to a central warehouse, or the book-keeper sending a month's figures to the accountant, would reduce their telephone calls to one quarter the duration they would have at 300 baud. Anyone transferring data over international phone lines should ensure they have this feature.

To get full benefit from the Nightingale however, you need PACE's Commstar RCM chip. This offers three different modes of operation:

1. To talk to PRESTEL.
2. To talk over the 'phone to some other computer terminal. This may be in another office or factory of your business, in your accountant's office, or may be a computerised service, such as a specialist database for your trade. An increasing number of such services are becoming available - no longer need every solicitor have a great library of case law, nor every doctor a room full of medical text books.
3. To talk to another computer over a direct wire connection (less than 20 metres away).

This is a welcome low-cost alternative to an Econet (or Torchnet) computer network, both of which are larger than necessary to link one manager to one book-keeper

For all these, Commstar offers a full range of functions. This was the first of the three packages I received and I soon connected with PRESTEL using far fewer keystrokes than with my former acoustic modem, "chatted" to it (sent instructions and received information in return), saved individual pages of data on disc to study "off-line" and at leisure, without the heavy telephone costs of studying "on-line". A timer told me how long had been using Commstar (but not, unfortunately, the 'phone call duration). I marked pages to return to them automatically and, joy of joys, for the first time, managed to record ("download") software transmitted by the Prestel computer, never previously achieved.

Although there are no options currently available, PACE tell me they are just around the corner. Watch this space.

Commstar's hand-book is a model for other manufacturers. It is not expensively produced: a hundred spiral-bound, A5 size pages, copied from a good daisywheel manuscript, but very accurate and free of "computerese". In particular it has:

1. a detailed contents list at the front,
2. an intelligent introduction, outlining scope and functions,
3. concise summary instructions for the expert who wants to start quickly and does not need detailed explanations,
4. a glossary of technical expressions,
5. a separate summary of all commands,
6. a full and accurate index,
7. a bright coloured, easy-to-spot-on-the-bookshelf, hard cover.

It is a pity that the Nightingale instructions (which came as separate duplicated A4 sheets) are not included. However PACE inform me that this is temporary, until they have received full approval for using the device over the British Telecom network, which they say is imminent.

Nightingale and Commstar together come at just under 160, including VAT, or you can buy them separately.

This is perhaps the most exciting of all because it is the furthest advanced in production of useful additional options. It is nicely made with the neatest control panel and imaginative extra connections as the rear for current and future options. Sadly the designers have made one disastrous error: it is too short for a standard B.T. telephone to sit safely on top, so it demands extra desk space which most executives will grudge. It also comes without a fitted plug and requires a 3 amp fuse.

The instruction manual looks like (but does not admit to being) a temporary one. The pages are loose and have only a paper cover. This is a pity because it is detailed, thorough and very well written, with a brief index, an excellent technical specification, a good fault finding section and clear diagrams, showing the different control settings for different applications.

It has the widest range of operations offering 600 and 1200 baud, half-duplex communication in addition to everything that PACE offers. This would be particularly useful for businesses that are going to send large quantities of data in both directions: for example, as the equivalent of a personal telex link, for computer conferencing, etc. It can also transmit at 1200 baud and receive at 75 baud for duplex. Like PACE it can be used over telephone systems that use American protocols. It has no control ROM of its own, Miracle will supply Commstar (at £34.95 inc. VAT - a slightly higher price than PACE!).

Miracle offers:

1. auto-dial
2. auto-answer
3. software control.

I have not been able to test these options fully as Miracle did not send one vital cable until too close to the editor's deadline. Also at the time of writing the auto-dialler is not approved for use over the British Telecom system.

The auto-dialler enables a standard rotating dial telephone to be controlled from the BBC keyboard. Up to ten numbers can be stored and the system will automatically re-dial numbers which are not connected at the first try.

Software control is achieved by a combination of disc with communication ROMs such as Commstar. It not only supports auto-dialling, but will select the communication mode from software (baud rate, protocols etc) and will pass the user's Customer Identity numbers to PRESTEL. As access to PRESTEL "by hand" is such a tedious business, this is most welcome - by judicious coding the user should be able to link with PRESTEL (or any other database) with a mere two or three key-strokes.

Neither of these options came with proper operating instructions; they are too new. Their development is still in a state of flux and readers should regard this review as merely an interim report. I shall keep you updated as the situation changes. The golden rule is to buy equipment with the potential to exploit the exciting developments that will undoubtedly take place within the next year. I am confident that both PACE and Miracle come within this category.

acoustic
to do with sound

acoustic modem
one that turns computer signals into sounds. which the telephone turns into telephone signals and vic-versa

auto-answer
device on a modem that allows incoming phone calls to access a computer without human intervention

autodialler
a phone that stores numbers in memory, so they can be dialled with one or two key-presses

bulletin board
a small computer database that can be read over the phone by another computer

baud rate
the speed at which signals are transmitted or received. 300 baud = 30 characters per second and so on

chat
to send instructions and receive information in return

download
record software transmitted to you by another computer

duplex (or full duplex)
system in which signals can travel freely in both directions

half-duplex
system in which signals can travel in only one direction; each operator has to switch when he has finished transmitting or receiving

hard-wired modem
one that omits the acoustic stage, turns computer electrical signals direct into telephone electrical signals

modem
a device that changes computer signals into telephone signals and vice-versa

PRESTEL
British Telecom's huge VIEWDATA system

protocols
telephone system's rules for transmitting signals

software control
system to control a telephone operation from software

transparent
allows normal telephone calls to take place as if it was not present

user-to-user communication
a computer talks over the phone to another (i.e. between office and factory)

VIEWDATA
database that can be read over the phone