This is a collection of commands to run on Cisco IOS platforms to help with troubleshooting voice connections. This is not a complete list, but just a few handy commands that I have used over the last few years.
General
See all Active voice calls on a gateway
router# sh voice call sum
Show only the active calls, not all the ports. Includes port, called number, and dial peer
router# sh voice call status
See more detailed information
router# sh voice port sum
See what happens when the specified number is dialed
router# show dialplan number 1436
See what dial peers are currently working
router# show dial-peer voice sum
T1 Controller (see if it's up)
router# sh controllers T1
See the active call information (including codec)
router# sh call active voice brief
MGCP Settings
router# sh mgcp
Test a Translation rule
router# test voice translation-rule
SIP
Show registration information
router# show sip-ua register status
Debugging
Show calls in and out of ports
router# debug voice ccapi inout
Inventory
See what's hardware is installed
router# sh inventory
See status of all DSPs
router# sh voice dsp
On Newer IOS versions, see exactly where the DSPs are installed
router# sh diag | i DSP
On Newer IOS versions, see what the hardware for WIC/VIs are
router# sh diag | i FRU Part Number
On Newer IOS versions, Look for DSP (or add "| i DSP")
router# sh inv
