Which two Cisco Unified CallManager tasks are required to route calls from Cisco Unified CallManager to the PSTN via an H.323 gateway? (Choose two.)

4
Cisco 642-447 Exam

A.
configure the IP phones with an external phone number mask

B.
add PSTN route patterns pointing to the gateway

C.
add a gatekeeper from the Device menu

D.
configure the signaling protocol used on the voice circuit

E.
configure the voice endpoints in Cisco Unified CallManager

F.
add an H.323 gateway from the Device menu

Explanation: