🚀 go-pugleaf

From  "John R. Levine, P.O.Box 349, Cambridge MA 02238-0349 (617-494-1400)" <johnl@ima.UUCP>
Subject: Why the Vadic 3400 protocol died
To: bbncca!telecom
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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