[Asterisk-Users] TDM400P FXS polarity reversal?

[Rich Adamson]

> Is it possible to do a talk battery polarity reversal on a TDM400P FXS
> interface?  Everything I can find seems to be referring to the
> procedure for detecting a battery reversal on a telephone company POTS
> line using the FXO interface, but not for actually generating one back
> to a station upon answer supervision.  I would assume that VoicePulse
> and VoipJet provide a way of signaling far-end supervision back to the
> originating Asterisk PBX...
> 
> Basically, my two questions are:
> (1) Is the hardware capable of even performing a reversal?
> (2) If the above is true, how would you make it happen in Asterisk?

The Silicon Labs spec sheet does not specifically indicate generating
a reversal is possible. Therefore, best guess is the integrated circuits
on the card does not support it, therefore asterisk has no means of
doing it.