Understanding The Hardware

 

Telephone systems for small businesses are the hottest part of the market today. New products -- and new competitors -- appear monthly.

Traditionally, telephones work either as a "key system" or as a "private branch exchange" (PBX).Key systems have lighted buttons ("keys") on every phone, displaying the status of each line. To call outside, you push the button of a line that is not in use. Modern PBXs, on the other hand, use mostly single-line instruments -- ones that look like residential phones. To get an ouside line, you first dial "9".

The term "line" here means a connection to the outside world. The telephone industry uses the term this way when referring to key systems. In PBX terminology, however, a line means an individual telephone or "extension," while connections to the outside are called trunks.

Generally, a key system is easier to use in a small office. The lighted buttons provide handy feedback. A key system allows anyone to fill in as receptionist from any telephone, because several calls can be juggled at once.

With more than about 3o telephones, however, bewilderment results when an instrument blinks like a Christmas tree. Then a PBX starts to make sense. In addition, single-line PBX instruments cost less than the blinking-light variety. With, say, 50 telephones, the difference can be significant.

But key systems carry their own cost advantage. The regulated tariffs for telephone lines serving a key system are frequently lower than for a PBX -- even though, from the point of view of the local phone company, the service is identical. "The logic is lost in history, "comments Harry Newton of Telecom Library Inc.

The next distinction to understand is between an electromechanical and an electronic system. The former is the old-fashioned technology; the latter is state of the art.Electromechanical systems generally use bulky cables containing 25 or more pairs of wire. In contrast, newer systems get by with two-pair or three-pair cables, which are less costly and easier to install.

In spite of its apparent technological obsolescence, the old-fashioned kind may still be worth considering. Newton's situation with his electromechanical system shows why. He has found a way to make room for additional lines by eliminating some of the nine current lines from certain phones in the office. It won't be an elegant arrangement -- Newton occasionally will have to run over to another desk to answer a call on a line missing from his own phone. But at least such improvisation is possible.

In other words, Newton says, electromechanical systems are "very forgiving." If an electronic system lists a capacity of 16 lines, there is not likely to be a way to squeeze on one more.

If you keep that warning in mind, though, the newer electronic systems have much else to recommend them -- namely, the many computer-controlled features that help make phone communication easier or less expensive.

The most up-to-date PBXs use digital signals. The older method, although it may use solid-state electronics, is called analog. The main benefit of digital has to do with "office of the future" applications in which workers might use computers linked together through the telephone wires. Since data travels most efficiently in digital form, a digital telephone system may adapt itself more readily to such uses.

Most observers agree that such applications won't become important in smaller businesses until late in the decade, if ever. But the typical new key telephone system stays in use for 12 1/2 years, according to John Malone, president of Eastern Management Group, a telecommunications research and consulting firm in Morris Plains, N.J. Farsighted managers may want to buy digital just in case. The majority of PBXs manufactured today still work on the analog method, says Malone.