I am currently working to install central station PBX's. Have bee for years and I understood the only PBX's being used were the Avaya and the Tadiran. Is this true?

If you could tell us a little more about the equipment, and your projects, please...

Can you define what you mean by a "central station PBX"? and by "have been for years..."

I know what a central station is, in the context of the alarm industry, and I know what a telephone PBX is.

I also know what the difference is between a telephone PBX and a telephone key system.

What I'm not clear on is how you are associating the two types of systems, and why you think that Avaya and Tadiran are the only manufacturers.

You're right, I forgot the Atlas 550.

My projects, for the last 8 years I work for a company that has been replacing the Atlas 550 with a Tadiran solution. We have the capability of handing off the ANI*DNIS* required by the Surgard and Bosch receivers. Added with replacing the 550, this allows the incorporation of a full blown PBX. I understand the only other PBX with this capability is the Avaya.

In implementation, we set between the carrier, the receivers and the central station operators. I am wanting to know if there is any other systems doing this?

The only Atlas 550 I've heard of is an Adtran unit.

That is the one, in most centrals that I've been in the Atlas routes alarm DID's out FXS ports and then voice calls are either sent over to a PBX via a PRI or a seperate PRI is used for voice.
Not trying to advertise here, with the Tadiran we have been able to replace both the Atlas and the existing PBX with a unified approach. It makes 2-way alarms easier to handle. I known the Avaya has capabilities to do this, I am wanting to know who else does.