Troubleshooting FXO Dialling Issues

1.      Call Flow:

The calls coming into the gateway from SIP side (sip server/phone) where in it will seize the respective FXO port (based on the dial plan) connected towards PSTN line.

2.      Symptoms of the issue:

Check if you face below symptoms after the call seizes the FXO port.

a. You get a dial tone after dialling the numbers 

b. The telco provider gives you the message as number dialled is incorrect.

Find below the basic log of a call from SIP to FXO POTS where FXO port 1 has got seized.

LOG: 03/10/2016 07:50:33.232 ROUTER   (I)R0bC00 FINDROUTE profile:23(To_FXO) plan:1

                call ref=[f10a00da]                            <-- SIP     [2,1] dest=NAME:0527781178,TEL:0527781178

                                                                               --> POTS    [1,1] dest=TEL:0527781178

admin  >

LOG: 03/10/2016 07:50:33.235 ROUTER   (I)R0bC00 call proceeding

                 call ref=[f10a00da]

admin  >

LOG: 03/10/2016 07:50:36.300 POTS     (I)R03Cb6 connect call

                 call ref=[f10a00da]

admin  >

LOG: 03/10/2016 07:50:36.330 SIP      (I)R03C27 connect g711Ulaw64k (Profile 1 - Voice)

                call ref=[00000000]

  3.      Solution:

Make sure you have the latest firmware on the Vega 50

Please make sure the line detection type has set properly based on your telco provider

There are 3 ways in detecting the line, which are as follows

             1) Tone detection

             2) Polarity reversal detection

             3) Loop current detection

a. Enable the Full Scale value for the POTS FXO Port Hardware Profile

b. Adjust the Digital Tx gain to -3

Once the above parameters are set as per your network requirement, make sure you have applied the same configuration by doing Apply and save the config