The type of channel used for the call. This value indicates what kind of endpoint the call is connected to.
PHONE
SIP
STREAM
VOICE_RELAY
The type of channel used for the call. This value indicates what kind of endpoint the call is connected to.
PHONE: A call from or to the telephone network.SIP: A call from or to a SIP endpoint.STREAM: A call to a stream.VOICE_RELAY: A call to voice relay service.