Let me start by saying, I'm not a Vodavi tech, but seeking some wisdom from the group.
We have a customer with a Vodavi XTS-IP. They have five locations. Four of the locations have Inter-Tel systems networked (Axxess and 5200's), the fifth location has the Vodavi. We installed four Inter-tel IP SLA units at that location and connected the single line exts to trunk positions on the Vodavi.
Here is the trouble, when someone from any of the Inter-Tel systems dials the hunt group for the IP single lines, voice mail on the Vodavi answers the call, they dial an extension and if the person doesn't answer, when that call forwards to voice mail on the Vodavi, the caller then hangs up. The IP SLA doesn't release from the voice mail and it ties up the single line exts and the voicemail port. The Inter-Tel system then gets an off hook alarm for the IP single line ext. The ports do free up, but it takes about 5 minutes. We have no settings on the Inter-tel switch to adjust for disconnect.
Any suggestions as to tweaks to the Vodavi that would assist with actually dropping the call when the caller hangs up?

It's the SLA's not sending an open-loop disconnect signal that's causing the problem. This would happen with any system, not just a Vodavi. By default, the XTS is configured to drop a call in the process of being transferred or on hold if a disconnect signal is received. Depending upon the version of software in the system, it can also be programmed to drop a call in progress IF the open loop disconnect signal is received by the SLA(s).

Are these systems on the same premises? If so, getting the signal sent by the SLAs is all you will need to do (assuming that the SLAs are capable of doing this. Remember that Inter-Tel may refer to this feature by another name, such as COD or CPC.

The voice mail can be tweaked for a maximum record time or to listen for reorder tone patterns, but there will still some level of nuisance tones recorded in hang up messages. Again, this isn't an issue inherent in a Vodavi system; they all depend upon a disconnect signal to operate properly.

Thanks, Ed. Your reply was what I was expecting - but not hoping for.
The systems are located about thirty miles apart and the SLA's are not capable of sending the open loop disconnect.
The Vodavi voice mail has been tweaked for record time. The re-order tone pattern might be something we can look into.
Thanks again for the quick, helpful response.
Bruce

You may also look at a third part CPC device, like the type that Mike Sandman sells.