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Octal FXS Card disconnect issue

I have the 8 port Octal FXS card in an Atlas 550 with some analog phones attached to a few of the ports. I have a Cisco router with an FXO card that has 2 lines connected to 2 ports of the FXS module. Calls work just fine between them. However, If the analog phone connected to the FXS port hangs up first there doesnt seem to be any disconnect signalling or tones making it to my FXO port to tell it the call disconnected, thus the port stays in the seized state after the fxs device hangs up. If the phone on the other side of the call hangs up first the port does clear. I have not found anything useful in data sheets or anyone having the same issue in the fourms to help me. Does anybody what method the FXS ports use to signal supervisory disconnect messages when the phone hangs up so that i can configure my Cisco FXO ports to see it and clear the call? According to the debugs i am running on the cisco router i am not seeing anything come in after the FXS phone hangs up. My ports stay off-hook as a result.

any help would be greatly appreciated!

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Re: Octal FXS Card disconnect issue

Thank you for using the ADTRAN Forums.

If the ATLAS FXS ports are configured in the DIAL PLAN, then by default, the FXS ports do not send any signal to indicate the "far end" has hung up. The ports can be configured to remove loop current for a set period of time by configuring the "Forward Disconnect" setting under the DIAL PLAN, USER TERM, in the IFCE CONFIG for the FXS port. The default setting is "Disabled" but this can be set to 600ms, 1000ms, or 2000ms for how long the ATLAS will remove loop current when the "far end" hangs up the call.

So if your Cisco (with the FXO ports) is device A, and it dials device B; when device B hangs up, the ATLAS will then remove the loop current on the FXS port connected to A for however long the Forward Disconnect is configured in order to indicate the call has been disconnected.

Hope this helps,