lauren%lbl-csam@vortex.UUCP (06/23/83)
From: Lauren Weinstein <vortex!lauren@lbl-csam> Of course, modems which give you a simple ability to plug in an A.C. power supply, or which have *well designed* battery assist, should not suffer from the sort of problems I mentioned. Unfortunately, most of these "phone line powered" modems do not have such features. Just as an aside, battery "assist" systems, if not properly designed, can have some interesting problems. I had one client once who kept having bizarre problems with one of his phone lines -- the volume would gradually drop off to nothing after about one hour of continuous use. It turned out that the line in question was installed via a cheap line carrier multiplexing unit, which used a NiCad battery (float charged off the phone line when the line was idle) for power. Unfortunately, after about an hour or so of use, the battery would be pretty well discharged, and the current on the phone line was inadequate to keep everything going. So ... We had to get telco to install an external power supply to correct this problem. --Lauren--