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Configure the East router similar to the West router. The East router connects to the PBX through an E&M VIC port 0/1. Enter
the following commands to configure a POTS dial peer for all East telephones:
East(config)# dial-peer voice 211 pots
East(config-dial-peer)# destination-pattern 1919555....
East(config-dial-peer)# port 0/1
Enter the following commands to configure a VoIP dial peer for telephones on the West router:
East(config)# dial-peer voice 221 voip
East(config-dial-peer)# destination-pattern 1408555....
East(config-dial-peer)# session target ipv4:192.168.19.27
East(config-dial-peer)# exit
East(config)#
Enter the following command to configure number expansion and to make it easy for East users to dial numbers on the West
router:
West(config)# num-exp 5.... 1408555....
Finally, configure the E&M port:
East(config)# voice-port 0/1
East(config-voice-port)# signal immediate
East(config-voice-port)# operation 4-wire
East(config-voice-port)# type 2
East(config-voice-port)# shut
East(config-voice-port)# no shut

Checking the E&M Configuration

If you configured the E&M interfaces correctly, you can place calls from a telephone served by one PBX to a telephone served
by the other PBX (using just the extension, if you configured number expansion). If you have trouble placing calls, ping the
remote router to make sure you have IP connectivity.
Note See the “Configuring Quality of Service” section on page 31 if you need to improve the quality of voice connections.
Configuring ISDN BRI NT/TE Interfaces
The ISDN BRI VIC provides digital connectivity for VoIP networks using the European Telecommunications Standards Institute
(ETSI) Net3 switch type. The BRI VIC presents an ISDN S/T physical interface that connects to a network termination (NT) or
terminal equipment (TE) device. With the ISDN BRI VIC, you can connect the Cisco 1760 router to a PBX network in NT or
TE mode, or to a PSTN in TE mode.
Each of the two BRI ports can operate in NT mode as the clock source or in TE mode as a clock slave. For example:
•A PBX line card connection provides the BRI interface with a clock source operating in NT mode, so that the VIC port
operates as a clock slave in TE mode.
•A PBX trunk card connection provides the BRI interface as a clock slave operating in TE mode, so that the VIC port operates
as a clock source in NT mode.
Figure 22 shows an example of a network using ISDN BRI voice interfaces.