Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.3 4.3bsd-beta 6/6/85; site ucbvax.BERKELEY.EDU Path: utzoo!decvax!ucbvax!bbncca.arpa!ima!johnl From: johnl@ima.UUCP Newsgroups: mod.telecom Subject: (none) Message-ID: <8510242037.AA16269@UCB-VAX> Date: Wed, 23-Oct-85 01:26:00 EDT Article-I.D.: UCB-VAX.8510242037.AA16269 Posted: Wed Oct 23 01:26:00 1985 Date-Received: Fri, 25-Oct-85 03:33:24 EDT Sender: daemon@ucbvax.BERKELEY.EDU Organization: The ARPA Internet Lines: 29 Approved: telecom@ucb-vax.arpa From "John R. Levine, P.O.Box 349, Cambridge MA 02238-0349 (617-494-1400)" Subject: Why the Vadic 3400 protocol died To: bbncca!telecom ReSent-Date: Thu 24 Oct 85 16:25:48-EDT ReSent-From: The Moderator ReSent-Sender: JSOL@MIT-XX.ARPA.#Internet ReSent-To: Telecom-Individual-Messages-List: ; ReSent-Message-ID: <12153743277.72.JSOL@MIT-XX.ARPA> There were several reasons. The most important is that Bell cheaply licensed their protocol to everybody in sight, while Vadic had only one licensee, Anderson-Jacobson (as far as I could ever tell.) There are also technical reasons. It used to be important that you could accoustically couple 3400 protocol and you can't couple 212 protocol. Since the advent of modular phone plugs, buy your own phone, and inexpensive modems that can pick up the phone and place calls by themselves, it's practically not an issue any more except for people who call in from their hotel rooms. Also, the 212 protocol was designed for easier LSI implementation, which is why the frequencies are an octave apart. Evidently, a 212 implementation, even before the Rockwell chip set, was simpler and cheaper than a 3400. Finally, I also gather that the 3400 protocol is not as much better than the 212 protocol as people used to think. That impression was gained from triple modems which had lousy 212 performance. Good 212 modems are about as good as 3400 ones. John Levine, ima!johnl, Levine@YALE