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FXO Hook-Flash with CallManager ver 3.x

I was reading today that ITS (IOS Telephony Service) supports the Hook-Flash feature on FXO VIC's. Does CM 3.3(x) support this?

I've had CallManager in my house for several years and had to have my LEC turn off call waiting due to the fact that CM could not request a Hook-Flash from any of its FXO interfaces.

Any Ideas?


Re: FXO Hook-Flash with CallManager ver 3.x

Since the hookflash is just a momentary break in the loop current on the FXS port and cannot be sent as an audio signal, the router passes the hookflash signal via dual tone multifrequency (DTMF) relay as the '!' character. The router with the FXO port then sends a short loop break which the external device sees as a hookflash. To properly pass the hookflash signal, the VoIP dial peers need to be configured for dtmf-relay h245-signal.

The physical port timers have to be adjusted to suit the characteristics of the handset on the FXS port and the duration of the hookflash loop break out of the FXO port as shown below:Check the below link for more inforamtion on how to configure