[USR-TC] Setting up Netserver 16 I-modem

Hi all, I have got a Netserver 16 I-modem. for setting it up I connected ISDN line to it (2 wires isdn line from telco connected to middle pins of RJ-45) and set "imodem interface" according to it's manuals. The modem lights on the box always blink amber, I dont know where is the problem. I tried setting different ISDN switch types but nothing changed. Can anyone give me a help to solve the problem? Thanks Shahin