Glossary-12
domain
A grouping of LAN nodes in TCP/IP networks that has been assigned a
logical name.
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 RS232 interface control signal that indicates that the data
communications equipment (DCE) is connected to a telephone circuit.
Usually a prerequisite to the data terminal equipment (DTE) issuing RTS.
DSU, data service unit
Data communications equipment (DCE) that replaces a modem in connection
to a dataphone digital servicer (DDS): A baseband device, often included in
the cost of the DDS circuits.
DSU/CSU
An external device that combines the functionality of a data service unit
(DSU) and a channel service unit (CSU).
See also
DSU and CSU. Contrast
with ISU.
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 RS232 interface control signal that indicates that a data terminal unit
(DTE) is ready for data transmission.
E&M
In industry usage, a signalling convention between voice PBXs. As related
to MICOM's voice/fax modules, a strapping option for compatibility with the
tietrunk side of a voice PBX. There are five types (Type I through Type V) of
E&M strapping options in domestic models, and three types (Types I, II, and
V) in the international and universal models.