Cisco IOS Voice Troubleshooting and Monitoring -- T1 or E1 Interface Troubleshooting - DocWiki

For E1 lines, look for "Line Code is HDB3" in the show controller e1 output. For T1 lines, look for "Line Code is {B8ZS ... debug voip ccapi inout-Traces the execution path through the call control API, which serves as the interface between the call sessi

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