CHANNEL STATUS
CHANNEL STATUS [channelname]
Queries the status of the channel indicated by channelname or, if no channel is specified, the current channel.
Return values:
0-
Channel is down and available
1-
Channel is down, but reserved
2-
Channel is off-hook
3-
Digits have been dialed
4-
Line is ringing
5-
Line is up
6-
Line is busy