[asterisk-users] Simple Queue Problem

[Lee, John (Sydney)]

I am running Asterisk 1.4.21.2

For reception, I defined a simple queue with one SIP phone as the only
member.

When I receive an incoming call, I test QUEUE_WAITING_COUNT to see if it
is > 0.
If it is > 0, then I will playback a message to tell the caller to be
patient and then do a Queue(<queue-name>).
If QUEUE_WAITING_COUNT is zero, then I will just Queue(<queue-name>, r)
to ring the receptionist phone without playing any message.

A problem arises if the receptionist is talking to someone on the phone.
In this scenario, QUEUE_WAITING_COUNT is also zero but I will need to
playback a pls-be-patient message as well.

So, I need to find out whether the receptionist phone is busy even if
QUEUE_WAITING_COUNT = 0.

Do you know if there is anyway, without dialling a SIP channel, I can
check if a SIP extension is engaged or not?