Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!accuvax.nwu.edu!nucsrl!telecom-request From: John Higdon Newsgroups: comp.dcom.telecom Subject: Re: 1A2 Providers and Telco Equipment Message-ID: <10572@accuvax.nwu.edu> Date: 7 Aug 90 09:26:29 GMT Sender: news@accuvax.nwu.edu Reply-To: John Higdon Organization: Green Hills and Cows Lines: 31 Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 10, Issue 549, Message 5 of 8 Robert Von Borstel writes: > And am I correct that even if I find said speakerphone, it's really > not a full duplex type? ie there's a split second where it switches > from send/receive. I know this is old stuff, maybe the new stuff > (merlin/digital) doesn't do it. While there exist full duplex speakerphones (I have one at the office), they are very uncommon and really don't work as well as the standard switched gain variety. The reason for this is a law of physics. Even if the unit has remarkably good trans-hybrid loss, there exists a feedback path from the speaker to the microphone. What happens on my unit is if there is any abrupt change on the line, such as a call-wait or the caller hanging up, there is an ear-shattering howl. The switched gain speakerphones do not have this problem at all and are totally non-critical concerning speaker placement. The better systems of this type switch directions almost instantaneously and are easy to talk over (my Panasonic phones seem fine). The worst ones chop off words, or become confused and prevent one party from hearing the other at all. Buying a speakerphone is a lot like buying a car. You really should test drive it before you buy it. John Higdon | P. O. Box 7648 | +1 408 723 1395 john@bovine.ati.com | San Jose, CA 95150 | M o o !