Had to use "Loop Start" instead of "Kewl Start" (fxsls in zaptel.conf and fxs_ls int zapata.conf) to be able to dial out."Kewl Start" causes asterisk to hang up right after the last DTMF digit has been sent. This is probably caused by the voltage reversal the central genrates, which would be seen as a drop of voltage on the line by the X100P card. Things worked fine after changing ks to ls. — Thanks to tzafrir!