The Music Network
This month Paul Gilby takes us back to basics to clear up some confusion about the fundamental principles of electronic data communication.
The first time you ever go on-line with a data system many people feel it's like magic! We've all read about it, we all understand the power of such technology, but when you get hooked up for the first time you get a feeling that you're dabbling with real magic. So how many people have enjoyed the benefits that this form of communication can offer? Surely only a relatively small number have actually tapped into data networks? In fact, huge numbers of people use them every day without noticing. How many of you have a cash card for one of those hole-in-the-wall banks? The truth is that data systems are everywhere; the real difference comes when you have the necessary hardware, and start to use the networks for yourself.
Let's look at what's involved in data communications. First you need a computer - any computer. Next you need a modem, a communications program to run on your computer, and access to a telephone line. Finally, the most important requirement is membership of a data system - imagine how useless a telephone would be if you were the only person to have access to one. In our case it's The Music Network (TMN), though all systems work on a similar basis.
To become a member you need to apply to TMN for an ID (identity) and a password. TMN will provide you with your ID, which is usually created from your name: Sound On Sound's ID is sos, the BBC Radiophonic Workshop's is Radiofonix, and so on. Each of the users on the system has their own private password, which stops you or I going onto the system and pretending to be someone else. So, if you tried to get on TMN as sos you would have to know our password, which we change every day to maintain security. We recommend that you change your password on a regular basis, and that you don't follow a predictable sequence of passwords like girls names. Password security is very important.
Setting up the equipment is often the most difficult aspect of computer communications for many people, simply because there are so many combinations of computers, modems and cables. There are dozens of variations and it's this area which generates 75% of all the problems that users have when trying to get onto the system. Once you're on, it's plain sailing.
Without delving into the technicalities - this article is supposed to be aimed at a basic level - most problems will occur with the cable that links your computer to the modem. This is because the computer serial ports via which the computer communicates with a modem (often labelled RS232 or RS423) are not as standard as you and I would like. Manufacturers use different connectors, and some 'standard' cables are designed for use with only one type of modem, etc. Owners of Atari ST computers will be pleased to hear that the ST accepts a standard 25-way D type connector and shouldn't create any problems, and a good PC compatible should have exactly the same connector.
The computers that cause the problems are the BBC Model B, many portables, and the Apple Mac. Between them, these use a variety of connectors which means that you either have to find a special cable or make one yourself. I would strongly recommend that you do not try and make your own cable, even if you rate yourself as something of a whiz with a soldering iron - it really is guaranteed to drive you crazy. Finding the right cable is a fairly easy business, but they are not generally about in large numbers and are therefore often out of stock. Owners of PCs which can house an internal modem should do themselves a favour and buy one just to avoid this cable hassle.
I hope I haven't put too much of a damper on the whole idea of going on-line with this little discussion of cables. Although it's possible to create a lot of problems by not checking on the compatibility of the computer and modem you intend using, these problems are easily avoided. Just remember to ask your modem stockist for advice on the best cable for your combination of computer and modem.
With the cable connected between the computer and modem, and the modem plugged into the phone socket on the wall, we can start! Load the comms software, follow the instructions in the TMN manual (which you will receive when you become a member) for the correct data setting and dial the phone number. But which number?
We've mentioned PSS in these pages before, but what is it? Well, 'PSS' stands for Packet Switched Stream, and this is the name given to the public data network provided by British Telecom - a data network rather than a telephone network. Although one carries conversation and the other carries data, both systems use the same phone lines and exchanges.
When you want to get onto a data system such as TMN, you dial your local PSS number, wait for the tone and then switch your modem on-line (this is all done automatically if you have an auto-dial modem). You then type in the data address of the TMN computer and the call is routed straight into its comms port, whereupon you'll be presented with a prompt on the screen of your computer asking for your ID and password. Having answered these correctly, you are finally presented with the TMN 'Welcome' screen and you're on the system!
What is actually happening during all this is that your computer is being hooked up to the central TMN computer in London, with just that one local phone call. So if you live in Manchester, when you dial your local PSS number the call is re-directed through to London, but your phone bill is only charged at the local rate. The beauty of PSS is that you can call from anywhere in the country and for the majority of people it's always at the local call rate. You can even travel around the country and call the nearest PSS number from wherever you are; you're not limited to just your home town number.
The Music Network, (Contact Details).
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