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.)

A.
add a gatekeeper from the Device menu

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

C.
configure the voice endpoints in Cisco Unified CallManager

D.
configure the signaling protocol used on the voice circuit

E.
add PSTN route patterns pointing to the gateway

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