Firmware inforation :U1911 V2R3C50SPC300, IP phone:7910 V2R3
Topology: IPPHONE--Switch- PBX(u1911)--PSTN(SIP trunk)
Issue description: after customer follow the product to define the emgerncy call ,the phone can't access the PSTN .
1. Check the emergency configuration on U1911.
a. check the prefix
show prefix dn 112
b.check the emergency call
show emergency call
c. check the emergecncy route analysis
d. check the the emergency call direction
after check above ,everything is correct .
2.make a debug trace on U1911. the phone didn't send the access domain in invite message .
3. add the setting on IP phone ,but it still not work . make a debug again . the U1911 send the 403 forbiden message to phone.
4.check the U1911 trunck setting , the virtual trunk activate the heartbeat ,but there isn't real peer side component . so ,the conenction was setted as unavailble . after switch off the setting ,the test was ok .