> I have more FXO ports on TDM400's than I have PSTN lines available for
> testing. When all the lines were used up (the FXO ports are all in zap
> group 2), and I did a Dial(Zap/G2/${phone},5) it thinks the Dial succeeded
> even though there is neither line voltage nor dial tone. Can at least the
> lack of voltage be detected? It would be good in case one of the phone
> wires fell out that it would just move on to the next outgoing line.
Yes, the chip set on the TDM card does provide flags for indicating no
voltage (disconnected), low voltage (something is off hook), and normal
pstn voltage (on-hook).
About three months ago, Mark added code that detected when a pstn line
was unavailable (eg, rj11 disconnected, damaged cable, someone disconnected
the wrong pstn line). The code created a problem for someone (I don't
remember
the details), and he changed the code to be a compile-time config option.
I don't have any past references to that other then from memory. Maybe
someone that can read code can find that option for you.