I have a remote location with a Zyxel P-2602HW-D3A ADSL modem (the one shipped with Telfort ADSL Internet in The Netherlands). It includes VOIP capabilities. When used in conjunction with the Telfort Telefoniedienst VOIP, it works fine. When used in conjunction with a 3CX PBX installation, the modem will crash and reboot after approximately 40 seconds of having a perfect open voice connection through VOIP. It happens each and every time I try it. It will register with 3CX without any problems, just when making a call it goes wrong. The modem will completely turn off (all lights go out) and reboot. After approximately one minute the modem has been rebooted and the connection is back up. Same thing happens when I place a call again. I can't figure out why it doesn't "like" communicating with 3CX PBX but it does with Telfort Voip. Probably a long shot, but has anybody else encountered these problems with this particular device or perhaps similar problems with another device and knows a possible solution?