An engineer receives an isolated report that the customer can make calls successfully from an IP phone to other IP phones, but receives an error recording when attempting to call someone over the PSTN. The user cannot recall the error recording to provide the specific error message. Which two steps should the network engineer take to begin troubleshooting? (Choose two.)
A. Enable debug isdn q931 on the gateway and have user make the same call from the IP phone to PSTN again.
B. Check the region used by the IP phone in Cisco Unified Communications Manager.
C. Test the call using Dialed Number Analyzer in Cisco Unified Communications Manager administrator.
D. Check the calling search space used by the line on the IP phone in Cisco Unified Communications Manager.
E. Check the gateway to determine which codec is being used by the appropriate dial peer.
