Grandstream FXO Gateway GXW410X does not disconnect calls

Grandstream FXO Gateway GXW410X does not disconnect calls


This article describes the call disconnection issue in Grandstream FXO Gateway GXW410X and the steps to capture the logs for troubleshooting. Most of the time, we have seen that FXO Gateway does not detect busy tones correctly causing the calls to hang up.

Case 1 :
If there are no busy tones heard over the IP Phone when the PSTN hangs up, the PSTN lines may be using a reverse polarity signal when hanging up. Please ‘Enable Polarity Reversal’ of FXO ports on GXW4108 and test again.

Case 2 :
If there are no busy tones upon call disconnect, please check if the “Enable Tone Disconnect” has been set to “Yes”, then use the ‘CPT auto-detection’ function on GXW4108’s FXO Lines > Settings > Lines Analysis to detect the busy tone parameters and apply the test results.

The More You Know

Configure the busy tone as ch1-8: f1= 450@-16 , f2= 460@-16, c=35/35; in GXW410X (Philipines)

Due to GXW’s tone-setting time unit being 10ms, while UCM’s unit is 1ms, c=35/35 is set instead of c=350/350. In addition, the busy tone of PSTN is single frequency, and GXW410x does not support single frequency detection very well, so it is set to f1=450 and f2=460. The settings of other signal tones may affect the detection of busy tones too.

How to Capture Debug Logs from GXW410x

1. When capturing the calls on the GXW410x, please use the “audio capture” function to capture the audio of the line :
– click “start continuous capture” before the call starts
– “stop capture” after the call is ended
– After the PSTN side hangs up, wait a while for 10 seconds.
– When the IP phones registered under UCM hang up, click “stop capture” > download the audio buffers.

2. Set up the Syslog at the DEBUG level

3. Parallel connection of GXW410x and UCM to capture Analog Trace

Figure 1 shows the parallel connection between GXW4108 and UCM to diagnose the busy tone detection

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