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Cisco 1751 Voice-over-IP Quick Start Guide
78-11259-05
Conventions
Conventions
This document uses the following conventions:
•
Commands and keywords are in
boldface
.
•
Optional keywords or arguments are in square brackets.
•
Variables for which you supply values are in
italic
.
•
Titles of publications and new words or concepts are in
italic
.
•
Information the router displays on the console screen is in
screen font
.
•
Information that you enter at the CLI is in
boldface screen font
.
Installing WAN and Voice Interface Cards
The Cisco 1751 router supports two slots that can be used to install either WAN Interface Cards (WICS)
or Voice Interface Cards (VICS), and one slot that can be used to install only a VIC.
If You Are Installing Voice Interface Cards
The router supports one to three Cisco voice interface cards (VICs). Each VIC provides two ports. You
need one VIC port for each voice connection.
Note
To transmit voice calls over an IP WAN, you need (in addition to the VICs) at least one WAN interface
card (WIC) in the router to provide the connection to the WAN.
There are four types of VIC interfaces, as shown in
Figure 3
:
•
FXS (foreign exchange station) interface connects directly to a standard telephone, fax machine, or
similar device. The FXS VIC interface supplies ringing voltage, dial tone, and similar signals to the
station. Ports on this VIC are color-coded gray.
•
FXO (foreign exchange office) interface connects local calls to a PSTN central office or to a PBX
that does not support E&M signaling. This is the interface a standard telephone provides. Ports on
this VIC are color-coded pink.
•
E&M is a signaling technique for two-wire and four-wire telephone and trunk interfaces. The E&M
VIC connects remote calls from an IP network to a PBX for local distribution. Ports on this VIC are
color-coded brown.
•
The ISDN BRI NT/TE voice interface card provides a client-side (TE) ISDN S/T physical interface
for connection to an NT1 terminating an ISDN telephone network and can also be configured to
provide a network termination (NT) interface with phantom power. Each of its two ports can carry
two voice calls (one over each ISDN B channel), for a total of four calls per ISDN BRI card. At
present, the ISDN BRI VIC does not support ISDN devices such as digital telephone, fax, or modem.
Figure 1
shows a typical VIC.
