FXO ports are giving a secondary tone.

Unanswered Question
Jan 25th, 2008

We have a cisco 1760 gateway with 4 FXO ports connected to POTS lines. When a call comes into the POTS line, it's being plared to an IP phone on call manager. When the user picks up the call in call manager. You hear a second dial tone on the call and then eventually times out and hear a reorder tone. Attaching a show tech and debug. We can be giving this second tone.



I have this problem too.
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jimjensen Fri, 01/25/2008 - 15:51

I had a similar issue. I found that my cross connects on the 66 block we off by one binding post. Try re-terminating you lines.

pcameron Sun, 01/27/2008 - 03:51

Loopstart signalling does not pass and digits. The only indication a LS trunk gives that a call is coming in is the 80Volts AC ring signal.

By default, the FXO port will sense the ring signal, go off hook and play dial tone. This is called two stage dialing. Your config is set up to do this.

To make the call work using 'single stage dialing' add the following command under the voice port -

connection plar opx

Where is the extension on the CallManager that you want to map the call across to.

When a call comes in with this config, the voice port senses the ring signal, then automatically makes a call to the configured number. This matches on the voip dial peer and rings on the IP phone. The voice port does not go off hook until the IP phone (or voice mail) answers the call. Since the voice port does not go off hook until the phone is physically answered, the PSTN caller hears a PSTN ringback tone as well.

pcameron Sun, 01/27/2008 - 05:46

I'm going off the config in the attached document -


voice-port 2/0

timing hookflash-out 50


voice-port 2/1

timing hookflash-out 50


voice-port 3/0

timing hookflash-out 50


voice-port 3/1

timing hookflash-out 50


Also, 'direct-inward-dial' should be removed off the POTS dial peers - this is not needed on analogue ports. The command is used for digital ISDN or CAS type trunks and is not necessary for analogue FXS, FXO and E&M ports.


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