Quintum A200 ……

Yeaph. That ghost exist.I understand that there are three phones on the house, and the Quintum A200 is conected to one of those three outlets. When a person picks up the phone and dials out, the phone attached to Quintum rings.
The quintum A200 is supossed to receive the ring voltage from the central office, and the IVR is disabled, pass the call to the phone attached to the FXS port.
The sequence is like this: Ring voltage present from central office ,into the FXO port. Quintum detects the ringing voltage(100 volt A.C. 20 hz) and pass the call to the FXS port ,where the phone is at.That is the way that works.
Now the trouble.The other two phone are on the FRONT of the A200. When they dial out, specially on “rotary” mode, they generate spikes on the voltage that comes from the phone company. Those voltages “spikes” trick the A200 to think that there is ringing comming from the C.O. and the A200 start ringing the phone attached to port one.

Solutions: Be sure that the other two phones are not on rotary mode. They should be DTMF.
Cheap solution. Plug the phone line into line one, but your phone into phone two.
You will not receive normal calls on that phone, only VOIP calls, or for outgoing calls only.
The A200 will still confused, but the ringing will go to the unused port.
By the way, Quintum does not have asolution for this trouble. I already tried.