Specifications

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Cisco 1751 Router Software Configuration Guide
OL-1070-01
DSP
Digital signal processor. DSP segments the voice signal into frames and stores in voice packets.
DTMF
Dual tone multifrequency. Use of two simultaneous voice-band tones for dialing (such as touch tone).
E
E.164
International public telecommunications numbering plan. A standard set by ITU-T that addresses
telephone numbers.
E&M
E&M interface uses a RJ-48 telephone cable to connect remote calls from an IP network to PBX trunk
lines (tie lines) for local distribution. It is a signaling technique for two-wire and four-wire telephone
and trunk interfaces.
F
Frame Relay
Industry standard for switched data link layer protocol that handles multiple virtual circuits using
HDLC encapsulation between connected devices.
FXO
Foreign exchange office. The FXO interface uses a RJ-11 modular telephone cable to connect local
calls to a PSTN central office or to PBX that does not support E&M signaling. This interface is used
for off-premise extension applications.
FXS
Foreign exchange station. The FXS interface uses a standard RJ-11 modular telephone cable to connect
directly to a standard telephone, fax machine, PBXs, or similar device, and supplies ring, voltage, and
dial tone to the station.
H
H.323
ITU-T standard that describes packet-based video, audio, and data conferencing.
HDLC
High-Level Data Link Control. A data link layer protocol that specifies a data encapsulation method
on synchronous serial links using frame characters and checksums.
I
ITU-T
International Telecommunications Union-Telecommunications standardization section.
M
Multilink PPP
Multilink Point-to-Point Protocol. This protocol defines a method of splitting, recombining, and
sequencing datagrams across multiple logical data links.
N
NANP
North American Numbering Plan. The format in North America is 1Nxx-Nxx-xxxx, with N = digits 2
through 9 and x = digits 0 through 9.
D