I have had different vendors say one works for XXX and one will not. Just what are the differences?

I know an ATA adapter allows quasi 2500 compatibility, but, not 100% on the ATA2's differences.

Also, had a vendor tell me the VMI was required to get DTMF through the port to our IVR.

This is all curiousity to me.

Not to mention the issues we have with Nortel not sending DTMF * or # via intercom channel.

This is anecdotal at best, but I've installed several Nortels with ATA-2's to IVR systems and also connected digital ports. All depends on the board in the IVR! The ATA does not have forward compatibility but the ATA-2 is backwards compatible. The VMI is forward on all platforms and software. I'm not sure on the latest revs though! The VMI was designed to provide Nortel prompting as it sits in front of an after market voicemail and of course analog connectivity! As to the DTMF * and # on intercom, I was recently asked out to a job site for a gate phone/controller. I had previously connected an analog via ASM for this use. I had to go back and "help" the alarm gate phone company. Thinking of the DTMF issue, I tried going to long tones and it worked every time.

The VMI can be programmed to send dtmf tones during certain conditions such as disconnect. It also will send dtmf received from a digital set key pad. Neither the ATA or ATA-2 will.

Unfortunately the VMI was discontinued.

Thanks for the info. Sure do wish VMI's were still available, would make the integretion required by our IVR easier.

Do ATA2's work on all versions of Nortel/Northern Telecom/Meridian/or your favorite name for them?

As far as I know, they will only work on Norstar systems.

As for "Northern Telecom", if you're referring to the "Vantage" line of systems...NO. These came out prior to the name change to "Nortel".