Client reports that they had the system drop all three calls at one time. They have three analog lines into the SPA400 and three times today, when all three lines were in use, they had the calls ALL drop. I have asked them to confirm with Ma Bell that call waiting is turned off on all the lines. We tested it two weeks ago and it was, I think. I remember getting a busy signal calling in as the fourth line, but it might have been caused by something else. Any other ideas? Thanks.