You can set the parameters under the appropriate pstn group. Below is an example of the settings. Hopefully you have the appropriate software to support it
Answer Delay Timeout = 60
Supervision = answer and disconnect(3)
In this example, the Tenor will answer the call in 60 seconds, if no one has actually answered the call.
The supervision option, tells the Tenor to look for call progress tones and audio.
Normally, if these options are not defined, the Tenor will make the call active as soon as it seizes the line.
Hope this helps!