Cisco 700 series, Installation Manual

Page: 77 / 118

Concepts and Descriptions 6-3
PSTN
Public Switched Telephone Network
RIP
Routing Information Protocol
Service Profile Identifiers (SPIDs)
Numbers assigned by the ISDN service provider that identify the ISDN B channels.
They are assigned only in North America. The SPID format is generally the ISDN
telephone number with several numbers added to it. Depending on the switch type
supporting your ISDN BRI line, your ISDN line might be assigned none, one, or two
SPIDs.
TCP
Transmission Control Protocol
TPAD
Terminal Packet Assembler and Disassembler
ISDN Ports
Cisco 700 series routers provide one basic rate interface (BRI). The ISDN BRI service
provided by your telephone service provider offers two bearer channels (B channels) and
one data channel (D channel). The B channel operates at 64 kbps and carries user data. The
D channel operates at 16 kbps and carries control and signaling information, although it can
support user data transmission under certain circumstances.
Outside North America, telephone service providers typically provide an S/T interface. The
S/T interfaces are four-wire (two pairs of two wires) interfaces that supports full-duplex
data transfer over two pairs of wires.
Inside North America, telephone service providers typically provide a U interface. The
U interface is a two-wire (single pair) interface that supports full-duplex data transfer over
a single pair of wires.