- D channel
A data channel of the ISDN interface. It is one of the three standard channels on a Basic Rate ISDN line. On a BRI-ISDN line, a D channel can carry signaling information and low-speed packet data at a rate of 16,000 bps. On a PRI- ISDN line, the D channel runs at 64,000 bps. See Basic Rate Interface (BRI-ISDN), B channel, Primary Rate Interface (PRI-ISDN).
- device class
A group of related physical devices or device drivers through which applications send and receive the information or data that makes up a call. For a list, see TAPI Device classes.
See direct inward dialing (DID).
- direct inward dialing (DID)
An ability provided by virtually all modern PBXs that allows an external caller to reach an internal extension by dialing a standard seven-digit telephone number without having to pass through an operator or attendant. See private branch exchange (PBX).