Why is the analog trunk always in busy status even when there is no call?
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”)

If the value is “No”, please change it as “yes” and test if it’s OK then.
If the value is “Yes”, please set up other parameters of Busy Detection. In the case that you can get the parameters from your service provider, please configure them directly.