In that case, the lines coming out from the PBX will have dial tone or voltage, and they should be plugged into the PSTN ports.
The rule is very simple: Using a single line phone (like the one at home),plug the phone into the line in question.
If you pick up the phone and you have dial tone, that means that the line is a FXS line and should be plugged only on the PSTN side of the Quintum.
If you look toward the Quintum, the PBX ports have dial tone, and even when it sounds wrong, they should not be conected to a PBX extension.
The lines with dial tone go to the ports on the Quintum that have NOT dial tone.
Phone lines from phone company->to PBX TRUNK ports->to quintum PSTN ports->PBX ports on the quintum to phones (users).
Another way to implement the Quintum is put it betwen the phone company and your PBX.
Phone company lines->quintum PSTN->quintum PBX to PABX trunk ports->
That was the original design of the Quintum, and you will relaize that now the names make sense.
In that particular configuration, all the calls from the PBX to the outside goes trought the Quintum.
The quintum “bypass” all the normal calls and re-route over I.P. the ones to long diatnce providers or overseas calls.
Most people avoid thsi configuration because the loss of quality/level that happens with all the calls going trought the Quintum.