Why Analog Trunk Keep Busy? – Yeastar Support

Symptom

Analog trunk is always in busy status even when there is no call. ( You can’t hangup the call)

Reason

It results from the incorrect configuration of “Busy Detection”. Please log in the Web Configuration Panel and check if the value of “Busy Detection” is “yes” in the Analog Trunk editing page (the default value is “yes”).

1) If the value is “No”, please change it to “yes” and test if it’s OK then.

2) If the value is “Yes”, in the case that you can get the parameters from your service provider, please configure them directly. Or you can try other busy detection setting by following the solution in the following.

Solution

Please follow the steps in the following:

Step 1. Login SSH.

For S-Series: How to Log in SSH of Yeastar S-Series VoIP PBX

For U-Series & Gateway: How to Login the SSH of Yeastar MyPBX

Step 2. Capture the FXO port signal.

Followed by this guide: How to Get the FXO/FXS/GSM Port Signal Capture

Step 3. Download the rx.raw file and analyze it.

Step 4. Use Cool Edit (a kind of software) to analyze the busy tone detail
Open the rx.raw file as
Sample Rate 8000
Channels Mono
Resolution 16-bit
Formatted the rx.raw file as 16-bit Intel PCM (LSB, MSB)

Figure Sample Format As

Figure Raw data

Example busy tone signal waveform

Usually, the length of the sound (on time) and the silence (off time) of busy tone are the same. In the example below, one cycle of the busy tone is 250 ms on, 250 ms off.