larry@uunet.uu.net> (04/08/90)
In article <5832@accuvax.nwu.edu> telecom@eecs.nwu.edu (TELECOM Moderator) writes: > line. Instead, the phone sat on a box with a speaker in the top of > it. Two metal fingers were fitted under the receiver, in the middle > section on top of the phone between the switchook buttons. Any loud > noise in the vicinity (such as the vacuum cleaner in general, but the > bell on the phone in particular) caused a relay in the box to close > its contacts. The early 1960's vintage answering machines that I recall used an inductive pickup coil which was slid under the telephone in order to detect ringing. This eliminated the, um, "vacuum cleaner problem". Other answering machines also used the inductive pickup coil in place of an acoustically-coupled microphone. <> Larry Lippman @ Recognition Research Corp. - Uniquex Corp. - Viatran Corp. <> UUCP {boulder|decvax|rutgers|watmath}!acsu.buffalo.edu!kitty!larry <> TEL 716/688-1231 || 716/773-1700 {utzoo|uunet}!/ \uniquex!larry <> FAX 716/741-9635 || 716/773-2488