Switch hook help

I am trying to hook up trixbox to an older phone system to provide auto attendant and other services. I need to know how to do a switch hook or a flash to get a dial tone and then enter a extension number. I have been searching for an hour now and can’t find a good answer to this. My misc destinations and applications are working fine, just need that dial pattern with a switch hook in it.

Thanks!

Why do you need to do a switch hook to get a dial tone. I’snt taking the phone off hook enough (i.e. simulate lifting the receiver/handset)?

I need to include the switch hook, or lift the handset, in my dial plan. For instance, a new call is transfered to asterisk by the old phone system, the ivr answers and says hello. The caller presses 1. 1 needs to transfer to a extension on the old phone system, so it needs to do a switch hook, or flash, to get a dial tone on the old phone system to then enter the extension to transfer to. Asterisk transfers the call and frees itself up to take another call.

Google is your friend:
http://www.voip-info.org/wiki/index.php?page=Asterisk+cmd+Flash