My config: OpenVox 12FXO 4 FXS, about 40 SIP accounts on Siemens C470IP and PAP2T. First problem: some devices log out without a reason (only on Siemens). I tried different IP's. Second problem: inbound connections on analog lines sometimes hung. The connection is over but on the FOP I see, that the line is not disconnected. It does not happen every time, but few times a day on different ZAP channels.