Which are characteristics of VAD?

A.
VAD is used with ADPCM voice connections only.

B.
VAD makes voice traffic bursty.

C.
VAD will add delay to a voice connection.

D.
VAD connections use less bandwidth on the trunks.

Explanation:
With VAD, voice data packets fall into three categories: speech, silence, and unknown. Speech and unknown packets are sent over the network; silence packets are discarded. The sound quality is slightly degraded with VAD, but the connection monopolizes much less bandwidth