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From: clements@BBNCCQ.ARPA (Bob Clements)
Newsgroups: net.micro.cpm
Subject: 150 baud terminals
Message-ID: <1940@brl-tgr.ARPA>
Date: Mon, 7-Oct-85 07:39:04 EDT
Article-I.D.: brl-tgr.1940
Posted: Mon Oct  7 07:39:04 1985
Date-Received: Wed, 9-Oct-85 05:52:40 EDT
Sender: news@brl-tgr.ARPA
Lines: 24

>> Anybody know what hardware was originally responsible for the
>> use of 150 baud? ... Who made the first 15 cps printer?

The first major printer at 150 baud  (maybe the first of all, I don't know)
was the Teletype model 37.  Its mechanism was a lot like the model 35,
but with a bigger type basket. It was Teletype's first
machine with lower case letters.  We used them on some of the early PDP-10
processors as consoles. [We = DEC engineering of about 1969.]

And the person who corrected the tutorial by saying that 150 baud
machines used two stop bits was wrong. The model 37 used one stop bit.

I think the 37 was the only machine I ever saw that was fully mechanical
at that speed. That is, the "UART" function (serial <--> parallel
conversion) was mechanical, not electronic.  It rattled its little heart
out at a good clip, but couldn't really stand up to the effort. They didn't
last long before wearing themselves out and dying.

/Rcc

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