Black Box 5000 manual 256, EBCDIC, Extended Binary Coded Decimal

Multiserver 5000

DIT, direct in termination — A service offered by a PBX which allows incoming calls to the PBX to be routed directly to a selected telephone or group of telephones without operator intervention. Billing does not start until the telephone answers.

DLC, data link control — A communications protocol that sets up, controls, checks, and terminates information transfer between two stations on a data link.

downline loading — The process of sending configuration parameters, or operating software, from a controlling device to another device.

DSP, digital signal processor — This microprocessor is used in voice compression and fax demodulation.

DSR, data set ready — An RS-232 interface control signal that indicates that the modem is connected to a telephone circuit.

DSU, data service unit — A DCE that replaces a modem in connection to a DDS: a baseband device, often included in the cost of the DDS circuits.

DTE, data terminal equipment — The equipment serving as the data source and/or destination. May refer to computer ports, terminals, and printers. Also, interface signals typically presented by this equipment.

DTMF, Dual Tone Multifrequency — used for call addressing in pushbutton telephones. Also known as Multifrequency Pushbutton (MFPB) in Europe.

DTR, data terminal ready — An RS-232 interface control signal that indicates that a DTE is ready for data transmission.

E&M — In industry usage, a signaling convention between voice PBXs. As related to the Multiserver’s voice/fax module, a strapping option for compatibility with the tie-trunk side of a voice PBX. There are 5 types (Type I through Type V) of E&M strapping options in

domestic models, and 3 types (Types I, II, and V) in international models.

EBCDIC, Extended Binary Coded Decimal

Interchange Code — An 8-bit IBM character code.

echo — The return of transmitted data to its origin.

ENQ, enquiry — A control character used as a request for identification or status in communications protocols. For example, in the Hewlett-Packard ENQ/ACK protocol, ENQ is sent by the transmitting device to determine if the destination terminal is ready for more data. See also ACK.

equalizer — A device used by modems to compensate for distortions caused by telephone line conditions.

<esc>, escape — An ASCII or EBCDIC character used to modify the meaning of the character that follows (dependent on defined protocol). It is often used to set equipment in different modes of operation or to position a cursor on a terminal.

fast busy signal — See Reorder.

Fast Packet multiplexing — A remote networking technique that dynamically combines various signals including voice, fax, async and sync data, video, and LAN onto one communications channel with 95% or better efficiency.

fax, facsimile — Transmission of hardcopy (written, typed, or drawn) images through a voice/fax channel.

Fax Demodulation — A technique for detecting a Group 3 fax signal on the voice line and reducing it to its original speed for transmission across the link (64 Kbps to

9.6Kbps). At the other side, the signal is recognized as fax and is sent to the appropriate device.

fax sharing device — A device used when a fax machine is shared between the Public Switched Telephone Network (PSTN) and the

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