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Cisco 1751 Voice-over-IP Quick Start Guide
78-11259-05
Configuring Voice-over-IP
Both PBXs in this example use E&M interface Type 2, with four-wire operation and immediate-start
signaling. The values for your configuration depend on your PBX and are available from your
telecommunications department or the PBX manufacturer. For more information about E&M interface
configuration commands, refer to the “VoIP Commands” chapter of the Cisco 1751 Router Software
Configuration Guide.
In this example, West users can dial 5 and a four-digit extension to reach telephones in the East Office.
East users can dial 5 and a four-digit extension to reach telephones in the West office.
The West router connects to the PBX through an E&M VIC port 0/0. This port is associated with a POTS
dial peer for incoming calls. But you no longer need to associate every telephone number with its own
port. Instead, you can configure a local dial peer as if all the West telephones (represented by a wildcard
destination pattern) are connected directly to this port, as shown in the following commands:
West> enable
Password:
West# configure terminal
West(config)# dial-peer voice 111 pots
West(config-dial-peer)# destination-pattern 1408555....
West(config-dial-peer)# port 0/0
Configure VoIP dial peers for outgoing calls and associate destination phone numbers on the East router
with that router IP address, as shown in Figure 20, and in the following commands:
West(config)# dial-peer voice 121 voip
West(config-dial-peer)# destination-pattern 1919555....
West(config-dial-peer)# session target ipv4:192.168.11.3
West(config-dial-peer)# exit
West(config)#
Figure 20 Linking PBXs over the IP Network (Remote Dial Peers)
Now configure number expansion so that numbers beginning with 5 (belonging to the East office) and
sent by the West PBX to the West router are expanded into the full destination pattern:
West(config)# num-exp 5.... 1919555....
Note You do not need to configure number expansion for calls from one West telephone to another West
telephone because the PBX switches those calls.
Finally, enter the following global configuration voice-port command to configure the E&M port:
West(config)# voice-port 0/0
West(config-voice-port)# signal immediate
West(config-voice-port)# operation 4-wire
West(config-voice-port)# type 2
22343
West East
408 555-xxxx
E&M VIC
0/0
919 555-xxxx
192.168.11.3
dial-peer voice 121 voip
destination-pattern 1919555….
session target ipv4:192.168.11.3
num-exp 5…. 1919555….
PBX
PBX
Source
Destination
IP cloud