sundance-communications.com/forum Forums TDM Business Telephone Systems Vodavi Telephones & Systems Disconnect Supervision.

I am going to be putting an STS with voice mail behind a PBX. The PBX is supplying 4 analog extensions that will be going into my CO card. The AA on the voice mail will be answering all incoming calls.

The problem I am going to have is disconnect supervision (Sandman calls it: Open Loop Disconnect or Calling Party Control). When the calling party hangs up, the voice mail never releases the analog port on the PBX.


I found a CPC Generator (MIS1I) from Sandman. I was wondering if anybody has used this product or knows of another product that fixes this problem. The MIS1I only supports one line, so I am going to have to get 4 of these devices. I was hoping that there was a product that was a single unit that accepted multiple lines.

Any help would be appreciated!

Just a Question, what PBX are you behind?

You should also post this in the general section. This is not unique to just Vodavi. I take it that the STS is not detecting the disconnect therefore not giving a inband disconnect to the voicemail.

Faytech: Not sure yet...waiting for a call back. Kinda hoping he can provide disconnect.

A6: Correct.

A follow up on Telecom_Robs question, The PBX was an older Rolm switch with no disconnect supervision on the analog ports. To add to the problem, there was a loud hum on all trunks (DID's) from the Rolm. The tech for the Rolm figured out the problem and got rid of it with the Telcos help. Still no disconnect, installed Sandmans product to fix. Over all, the hum was causing the major problem for the VM/AA and with low volume in general, the internal VM thought the caller had stopped talking and asked "are you done"?. It turns out that the area in question has major bad humming on almost all trunks and is still a bit of a problem on their main BTN. In the end, the customer likes the phone system alot.

You will probably need to get the PBX to send a DTMF string as a disconnect code to the voicemail system. Call the vodavi voicemail and press the * key serveral times
Im pretty sure this will generate a disconect if so find out if the PbX can do this I have had the same problem pulling dial tone off a router and having the router set up to do this fixed it.