This unit will not ring a standard Vodavi 2800 series SLT phone on a station to station call. Not a ring assignment problem. If the 2800 series phone is replaced with a standard SLT of another brand, the phone will ring on a station to station call. Both SLT sets have electronic ringers.
Question: What generates the ring on a Traid S? All others use a "ring Generator" I assume the Traid S uses an On Board Ring generator. Is this a board problem? I suspect it is.
Any help is appreciated.

Well, don't mean to as a stupid question, but the 2800 does have a ringer off/high/low switch, not turned off is it?

Triad S has built in ring gen on the slt card. I don't think it provides a full 90 volts AC however.

I recently had a service call for a 2801 not ringing on an XTS. Found the B/Z switch near the data port was in the wrong position. Supposedly, this only affects the message waiting light operation, but in this instance, it also affected the ringer.