Cisco Cisco IOS Software Release 12.2(13)ZH

For more details on the feature, refer to the following URL:

For information regarding the features supported in the Cisco IOS Release 12.2 T, refer to the 
Cross-Platform Release Notes and New Feature Documentation links at the following location on 
Cisco.com:

This URL is subject to change without notice. If it changes, point your web browser to Cisco.com, and 
click the following path:

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 Technical Documents

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 Release 12.2

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 Release Notes

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The following sections describe important notes concerning the new software features supported by the 
Cisco 1700 series routers for Release 12.2(13)ZH.

When you have insufficient available DSP channels and attempt to configure more PRI channels 
configured on a T1 or E1 interface in a router, only as many number of voice ports as the DSP channels 
are created. However show running-config command output will say that all PRI channels are 
configured. In this case, if you assign this PRI interface to a trunk group, the output of the show trunk 
group command would only take all the PRI channels that are configured and not the available PRI voice 
ports.

Change extended echo cancellation as the default setting, and hide g165 echo cancellation configuration.

This feature provides an alternative to the default Cisco-proprietary G.165 echo canceller (EC). The new 
extended EC provides improved performance for trunking gateway applications and provides a 
configurable tail length that supports up to 64 ms of echo cancellation.

The Cisco IOS command-line interface (CLI) has been modified to make the extended EC the default on 
the Cisco 1700.

The extended EC offers the following improvements over the Cisco default EC:

Complies with the ITU-T G.168 (2000) standard in addition to maintaining support for the old

ITU-T G.165 standard.