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Cisco 1751 Voice-over-IP Quick Start Guide
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Configuring Voice-over-IP
Checking FXO Configuration
If you configured your FXO interface according to this example, you can place outgoing calls over the
PSTN. If you have trouble placing calls, use the show voice port command to make sure that the VIC is
installed correctly. Use the show dial-peer voice command to make sure that the data you configured is
correct, and test the PSTN by connecting a handset directly to the PSTN outlet and placing a call.
Note Refer to the section “Tuning Parameters for Real-Time Voice Traffic” if you need to improve the quality
of voice connections.
Configuring E&M Interfaces
If you have more than a few voice users at each location, the cost of voice ports and routers and the effort
needed to configure dial peers for all the combinations of origins and destinations increases rapidly. In
this situation, it might be more efficient to use a PBX at each location to switch local traffic and direct
incoming calls and then use E&M VICs to connect the PBXs over an IP network.
Figure 19 shows a company with two offices, West and East. Each office has a PBX to operate its internal
telephone network, and the IP network carries voice traffic between the offices. Each PBX connects to
an E&M VIC port in the router.
Figure 19 Linking PBXs over the IP Network (Local Dial Peers)
To configure E&M voice ports, you need to use the following commands beginning in privileged EXEC
mode:
22342
West East
408 555-xxxx
E&M VIC
0/0
919 555-xxxx
192.168.11.3
dial-peer voice 111 pots
destination-pattern 1408555….
port 0/0
PBX
PBX
Source
Destination
IP cloud
Command Task
dial-type {dtmf | pulse} Select the appropriate dial type for out-dialing.
signal {wink-start | immediate | delay-dial} Select the appropriate signal type for this
interface.
cptone {australia | brazil | china | finland |
france | germany | japan | northamerica |
unitedkingdom}
Select the appropriate voice call progress tone for
this interface.
operation {2-wire | 4-wire} Select the appropriate cabling scheme for this
voice port.
type {1 | 2 | 3 | 5} Select the appropriate E&M interface type.