Outside forwarding issue on MiVoice 250

[Tripoth]

Client forwards extension to cell phone. Works fine.
After about 2 to 3 minutes the call remains connected to the cell phone but calls back into the main office location where people can pick up the call and join as if in a conference call.
How do I keep the call from ringing back into the main office on an outside forward.
There has to be a timer or flag somewhere?

 

[sarond]

Correct, it is a timer for Unsupervised CO (Limits the duration of outside calls transferred or forwarded to outside numbers before recalling the primary attendant.)

System > Timers and Limits > Unsupervised CO (Value from 1 - 255 minutes)