A. It does not use VoIP WAN bandwidth when an agent is answering the call.

B. It requires only limited system and network management skills at remote sites.

C. It requires only a small data switch and router, IP phones, and agent desktops at remote sites for a few agents.

D. PSTN trunks for incoming traffic connect to data centers for efficiency.

E. Calls extend over the WAN only while calls are in queue.

F. Small remote branches require PSTN and SIP trunks, in addition to the ones needed for local POTS lines for emergency services (911) in the event of a WAN link loss.