Lines remain hung up after a call, sometimes for days.

[KenanR]

BACKGROUND

Corporate system. 8 locations, with a total of 20 gateways around the country that run back to a primary and backup corporate location.
Asked if we could place a MG450 at a retail location off our corporate system. No issues with proof of concept so it was setup last Fall. A total of 4 loop start lines from telco.
ISSUE: Intermittent issues with lines not disconnecting after a call. The call shows up as in service/active but not connected to anything.
Added the trunk group to CMS and have been tracking there. When the CM shows not connected to any port, the CMS shows the initial VDN 555-1010. Sunday 5/6/18 I accessed the system. CMS showed 2 lines idle for 329 minutes, and 2 lines seized inbound for over 2700 minutes. I checked back and they were hung up since Friday afternoon. I busied/released the trunks and they have been ok since.

I had Telco visit who reported no trouble found with the lines.
I'm open for any thoughts/suggestions.
Thank you.

Supporting information is attached.

 

[joe2938]

have line provider enable disconnect supervision, common problem for these type of trunks

 

[KenanR]

Thank you for the post. This location was installed, and the trunk group was configured as loop start lines and disconnect supervision is Y on that trunk group. Is this an option from Telco end only available on pbx trunks? I emailed my Telco contact who hasn't been the most helpful yet.

Thoughts?

Trunk Type: loop-start

TRUNK PARAMETERS

Outgoing Dial Type: tone Cut-Through? n
Trunk Termination: rc Disconnect Timing(msec): 500

Auto Guard? n Call Still Held? n Sig Bit Inversion: none
Analog Loss Group: 6 Digital Loss Group: 11
Trunk Gain: high

Disconnect Supervision - In? y Out? n Cyclical Hunt? n
Answer Supervision Timeout: 10 Receive Answer Supervision? n
Administer Timers? y
XOIP Treatment: auto

 

[joe2938]

yes they the line provider need to enable disconnect supervision as well

 

[KenanR]

Thank you. Back through the LEC, to ask Telco about adding this to loop start lines. If needed then at least setup a phone call. They offered a vendor meet, but I'm going to ask for a joint phone call as I don't believe a vendor meet is needed.

 

[dialtonebone]

If they aren't responsive, perhaps consider converthing them to ground-start trunks which have supervision whether you want it or not. You could also do a partial PRI which is definitely the preferred option in all cases but may also require more change than desired.