> I just bought a X100P from digitnetworks.
> It is supposed to be a FXO card, but there are 2 rj-11 plug on the card.
> One is labelled "phone" and the other "pstn". When i
plug the "pstn" on
> the wall and the "phone" on my analog phone, everything (incoming
and
> outgoing calls) works like before (without asterisk).
> AFAIU, i should have an FXS card in my box to be able to use my analog
> phone, so why does it work this way ?
The two rj-11 jacks are wired in parallel. There isn't any support
for fxs on either jack.
> Second question, what is the cheapest card to use one analog phone only
> (TDM400 is too expensive). I read there's a S100U which seems to be a
> single FXS card, but I can't find a webshop selling it.
My understanding is the S100U is old and discontinued; don't spend
any money on it.
The least expensive but reliable fxs approach is probably using an
external ata device. Something like the cisco ata186, sipura spa1000,
or the sipura spa3000 (which has both an fxo and fxs port on the
same box).
You should be aware the majority of the x100p cards (and compatibles)
use a chipset on the card that was designed to meet US telco impedence
standards. Trying to use those cards with other country standards
will likely end up with echo that negatively impacts all conversatons.