Ring group time limit ignored on outside number

I have a ring group with an phone number in it followed by a #. It rings the number but ignores the number of seconds (10) I set for the ring time limit.

I also put an extension in the group to see what happens and it only rings the ext for the set number of seconds. It just continues to keep the outside line open and ring that number until it’s voice mail picks up after about 30 seconds.

The system is Asterisk and dahdi 2.4.0 with freepbx 2.7

Is this a bug or a limitation?

If so what other ways can I get an inbound call to the pbx to ring my cellphone for 10 seconds and then call my home phone?

I tested the exact same scenario on a nearly identical system with SIP trunks instead of POTs lines and it works. Does this give anyone a clue what my problem could be?

Is it some switch in my dahdi conf that needs to be set?

Someone on the Digium forum said this might be a “line supervision” issue but wasn’t more specific than that. I assume this means kewlstart vs. loopstart. The carrier is Cincinnati Bell so I have it set to kewlstart as per their instructions. Is there anything else in Dahdi that I may need to set?