Specifications

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Cisco 1751 Router Software Configuration Guide
OL-1070-01
Troubleshooting Tips
If you are having trouble connecting a call and you suspect the problem is associated with the voice-port
configuration, you can try to resolve the problem by performing the following tasks:
• Ping the associated IP address to confirm connectivity. If you cannot ping your destination, refer to
the Network Protocols Configuration Guide, Part 1 for Cisco IOS Release 12.1T.
• Use the show voice-port command to make sure that the port is enabled. If the port is offline, use
the no shutdown command.
• If you have configured E&M interfaces, make sure that the values pertaining to your specific PBX
setup, such as timing and type, are correct.
• Make sure the VICs are correctly installed. For more information, refer to the Cisco WAN Interface
Cards Hardware Installation Guide.
Fine-Tune E&M Voice Ports
In most cases, the default values for voice-port tuning commands are sufficient. Depending on the
specifics of your particular network, you might need to adjust voice parameters involving timing, input
gain, and output attenuation for E&M voice ports. Collectively, these commands are referred to as
voice-port tuning commands.
If you need to change the default tuning configuration for E&M voice ports, use the following
commands, beginning in privileged EXEC mode:
Command Task Valid Entries
Default
Values
Step 1
configure terminal Enter the global
configuration mode.
Step 2
voice-port slot-number/port Identify the voice port you
want to configure, and enter
the voice port configuration
mode.
Step 3
input gain value Specify (in dB) the amount of
gain to be inserted at the
receiver side of the interface.
–6 to 14 dB 0 dB
Step 4
output attenuation value Specify (in dB) the amount of
attenuation at the transmit
side of the interface.
0 to 14 dB 0 dB
Step 5
echo-cancel enable Enable echo-cancellation of
voice that is sent out of the
interface and received back
on the same interface.
Step 6
echo-cancel coverage value Adjust the size (in
milliseconds) of the
echo-cancel.
8, 16, 24, and
32 ms
16 ms