What You Need To Get On-line

 

To use on-line databases, you need either a so-called communicating terminal or a microcomputer, modern, and communications software. If your micro doesn't already have one, you will also have to buy a serial communications card.

Communicating terminals have modems and appropriate software built in. Some slower-printing terminals, such as the LEX-21, by Lexicon Corp. of Miami, in Fort Lauderdale, Fla., are selling for as little as $395. Many new computers, such as the popular Radio Shack TRS-80 Model 100, do have built-in communications software and modems, although the modems usually operate at slow speeds.

Modems, which range from shoebox-size to boards that fit inside a computer, turn data bits into tones for sending over phone lines (modulation), and turn the tones back into electronic pulses when they arrive at their destination (demodulation). Some are "intelligent," capable of automatically dialing a telephone number and logging on to a database service.

Communications software controls the operation of the modem and its interface with other peripherals, such as a printer or disk drive. It also lets you down-load an on-line search into your computer's memory. You can then go off-line to edit, print, or simply read the material at your leisure.

Modem and communications software should be bought together, since some packages are designed for use with specific modems, and both modem and software may be tailored to a certain micro. To make sure everything works together properly, ask the salesperson to hook it all up in the store and demonstrate it.

The most important variable affecting a modem's price is its speed: It will operate either at 30 or 120 characters per second (300 or 1,200 baud, or bits per second). You can buy 300-baud modems for about $100 (the Hayes Smartmodem 300, the market leader, costs $289), but most people eventually find 300 baud aggravatingly slow for reading on-line; Now, 1,200-baud modems have reached the $500 to $700 range, down about 15% from last year, and will continue to drop.

Communications software packages cost from about $50 to $250, depending on their capabilities. Your choice, however, may be narrowed by the kind of micro you own, and the type of modem. These programs also function at 300 or 1,200 baud. It is useful to buy a package that will work with a word processing program, so you can easily integrate database-search records with other files you may have. The size of the software package's "RAM buffer" is also important. The buffer, which governs how much data you can down-load for later use, may be as small as 4K (4,000 characters). Or, more typically, the package might transfer automatically the contents of the buffer to disk, giving, effectively, unlimited capacity.

Like some modems, communications packages may allow automatic phone dialing and logging on. For example, you could set your system to dial into Dow Jones News/Retrieval Service while you sleep, thereby taking advantage of lower rates. Some programs will accommodate only five or six telephone number and log-on combinations; others are more generous.