Direct Inward Dialing
<communications> (DID) A service offered by telephone companies which
allows the last 3 or 4 digits of a phone number to be transmitted to the
destination exchange.
For example, a company could have 10 incoming lines, all with the number 234
000. If a caller dials 234 697, the call is sent to 234 000 (the company's
exchange), and the digits 697 are transmitted. The company's exchange then
routes the call to extension 697. This gives the impression of 1000 direct dial
lines, whereas in fact there are only 10. Obviously, only 10 at a time can be
used.
This system is also used by fax servers. Instead of an exchange at the end of
the 234 000 line, a computer running fax server software and fax modem cards
uses the last three digits to identify the recipient of the fax. This allows
1000 people to have their own individual fax numbers, even though there is only
one 'fax machine'.
Dictionary of PC Hardware and Data Communications Terms.
(1997-06-29)
Nearby terms:
directed graph « Directed Oc « directed set «
Direct Inward Dialing » directional coupler »
Directly Executable Test Oriented Language » direct
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