Analog phone from PSTN call to U1911 VU then transfer to extension failed

Hello, dear!

Nice to meet you in the community!

Today I will share a solution to analog phone from PSTN call to U1911 VU then transfer to extension failed.

Issue Description

Some customer sites, U1911 used AT0 trunk. mobile called to VU then transferred to extension ok. But analog phone from PSTN called to VU then transferred to extension failed,  the phenomenon was that after hearing welcome voice then dialed extension number, the system no reacts, this means the system can not detect the signal from AT0 trunk when calling from the analog phone.

U1911 version is V200R003C00SPC200.

Solution

Depend on the testing comparison, all the testing scenario is same except the caller.usually for this issue, we try to resolve like this:

1. Log in to the web management system, and choose Trunk > Trunk Configuration > AT0.
   

2. Click a line or the blue icon for a peer office. In the displayed window, click Line Parameter Mode.
   

3. Select an FXO port, set Type to Customized, check and adjust parameter settings by referring to the following table, and click OK.
   

4. If the RX gain is too low, the receiver may fail to detect signal tones.
   

For this site, change the RX gain from web interface to 8dB depending on the FXO line.

Thanks!