My telephone line came unplugged from the modem. I have tried to plug it back into the modem but I still get the "check phone line" message. It doesn't seem to matter which spot I plug the line into, it still won't work. I have unplugged all lines for at least 60 seconds and I still have no dial tone. I need to know which ( for lack of a better word) hole in the back of the modem.