atcomsystems.ca/forum Forums General General Telephone & Systems Information Looking for device to send DTMF upon disconnect

I've run into an issue while doing an integration with a nurse call system, where the nurse call system expects the user to dial a digit to inform the nurse call to disconnect.

When a nurse receives an alert on their wireless IP phone, triggered by a patient call on the nurse call, the nurse has an option to accept the alert, and then to call back into the room and speak to the patient through the audio channel of the nurse call system (via my analog port and the nurse call system's "wireless telephone interface"). If the nurse presses the End button on their phone, the nurse call fails to detect the disconnect, and holds the line open until my analog port returns an off-hook "howler", and then eventually the port disconnects. The only option I have on my system is to send a typical disconnect notification (drop of loop current or battery reversal), but I don't have an option to configure a DTMF digit to be sent prior to disconnect. As mentioned above, the nurse call expects the nurse to dial a specific digit on their phone, prior to hanging up, to trigger the nurse call to disconnect the port.

I have two options: replace the analog "wireless telephone interface", on the nurse call system, with a SIP integration ($$$), or find a Viking Electronics-type device that will detect my drop in loop current or battery reversal and send a pre-programmed DTMF digit to the connected nurse call system. My choice, if something is available, would be to find something to add in between, to do the latter.

I've found devices from Viking Electronics and Sandman that perform functions due to lack of disconnect notification, but so far I've been unable to find something that does exactly this. It seems like something that should exist, maybe for interfacing phone systems with voicemail systems, where the voicemail system is expecting a digit (such as A) that the phone system is unable to send it.

Any help is greatly appreciated.

Have you contacted the equipment company to see what solutions they offer?

Can you assign the port to be and external voicemail port then the phone system should send the disconnect tone.

What phone system? Does the system support disconnect supervision?

I used a box from Sandman several years ago that was programmed to look for a programmable range being received on the line and convert to a user assigned digit or CPC to be output to the paging equipment. The paging equipment needed to see "a" for disconnect. I was able to program the adapter to see the digit sent for disconnect or amount of silence inbound and to send a digit "a" out. Don't see the same box but Sandman offers a CPC Generator that can be programmed to sent a CPC signal after a silence duration so that may be able to help. Part number DS16A. I'll look and see what else i can dig up.

This was something similar to what I used... I would call to see if it is still in production.

http://www.sandman.com/wizard.html#DTMFToneGenerator

Dave (RBF), I think that's exactly what I was looking for, but wasn't previously able to find. I'm going to call and see if it can play the DTMF in response to CPC or something other than another digit.

In response to the other questions, the phone system side is a Cisco analog voice gateway (VG224), using H323. It's not capable of being setup as a voicemail port; I wish it could be, since that would have been too easy. Cisco has said the gateway can't do what I'm asking to have it do. It's actually something I can do via TCL script on the gateway, from what I've read, but Cisco TAC doesn't support TCL scripts, and our Cisco partner doesn't have any experience writing TCL scripts; that was basically a no-go, unfortunately.

The nurse call manufacturer has said they can't do anything about it; we must simply send the DTMF for disconnect. That wasn't helpful. If I switch from their analog wireless telephone interface to their SIP interface, the DTMF is not required for disconnect. I'm still waiting on a quote for the SIP solution, but I've already been told it's pricey.

If Sandman's product works, even at $75.00 each, I'll still be money ahead.

Thanks, all, for the responses!

Justin

I contacted Sandman, and was told the DTMF generator would likely not be able to do what I need it to, but he was going to check to see whether a custom configuration would be possible, to basically do the opposite of what the CPC generator is designed to do. I'll update this thread when I hear back.

Thanks!

Justin