able to detect line in use without resorting to dialtone detection?

[cdkdang]

need to know whether it's possible for an external serial hardware modem to detect whether a line is in use via extension phone without the modem actually going on-hook and detecting dial tone?

Purpose is to use the modem as a call recorder.

My plan is upon ring detection check whether it's being picked up by a handset. if so go on-hook start recording the order. stop recording upon hang up signal.

I don't want to resort to dial tone detection because this could inadvertantly pickup to call or mess with the next incoming call (either picking it up or causing the next caller to get a busy tone).

 

[pansophic]

I don't recall ever having seen a modem that detected loop current, so I don't know of a way to detect the line being in use. CTI cards frequently can detect changes in loop current, but I don't recall ever having seen one capable of detecting the change in loop current caused by taking a phone off-hook on the line.

But you can use an Asterisk PBX to do this at a very reasonable cost.


pansophic