Hello. I am trying to configure a FXO port connected to a standard POTS line on the TELCO network for outbound dialing. I have a SIP trunk between an IVR system and CUCM that calls customers with a message. Right now this is in a test environment using the analog line mentioned above. The problem is that SIP is telling the IVR that the call is connected as soon as the call leaves the IVR to CUCM. This results in the message to the customer being played immediately. It appears that the analog line is getting translated to being connected to the SIP trunk before the far caller picks up. I have tried the battery-reversal answer detection on the voice port but this results in the message never getting played. Do I need to configure something else on the voice port to detect the call pickup? Thanks!
Very few telcos support call connnection supervision on analog circuits. You can ask them if they do, assuming the will even understand what is that you want. If you want reliable call setup supervision, use ISND BRI or PRI.
Very few telcos support call connnection supervision on analog circuits. You can ask them if they do, assuming the will even understand what is that you want. If you want reliable call setup supervision, use ISND BRI or PRI.
Hello Paolo. I just spoke with the guys here at the local CO and they informed me that the analog lines use a tip and ring reversal which basically they switch the polarity of the -48 VDC signal when the far-end connects and then reverse it back when the call gets disconnected. What is interesting is the fact that when I implement battery reversal answer on the voice port the message never plays to the caller. I need to hook wireshark up to the SIP trunk and see if the SIP connect message never goes through which is what I expect. As soon as I set the port to no battery reversal the message plays but it starts as soon as the call is sent to CUCM from the SIP IVR. The far-end receiver of the call may get part of the message or none of the message depending on when they pick the call up. Is there any other settings to adjust with the battery reversal answer command? Also is there a debug I can run to see if the FXO port is picking up the reversal from the TELCO?
