chips vs chad

Rod Smallwood rodsmallwood at btconnect.com
Tue Apr 6 04:27:43 CDT 2010


As ASR33's were the terminal of choice (leastways on DEC they were)
You might say in the US communications and data merged at that point. 

Teleprinters used five level Baudot code and Teletypes used ASCII. 
In fact as very junior engineer in the late 1960's whilst working at Harwell
I designed and built a box to drive Creed M75 tele-printers(We had loads of
them) from a serial ascii output on a PDP8. Great fun .. a shift register to
clock in the serial data. A Karnaugh mapped diode matrix to change the codes
from ASCII to Baudot. A character buffer made from bistables and another
shift register to go from parallel back to serial. It only worked because
the Creed was faster than the TTY output from the PDP8.
Integrated circuits used er none!

  

Regards 
 
Rod Smallwood
 

-----Original Message-----
From: cctech-bounces at classiccmp.org [mailto:cctech-bounces at classiccmp.org]
On Behalf Of Brent Hilpert
Sent: 05 April 2010 22:52
To: General at invalid.domain; Discussion at invalid.domain :On-Topic and
Off-Topic Posts
Subject: Re: chips vs chad

Somebody might check some manuals for teletypes or paper-tape punches for
the
'official term' used for the punch detritus from paper tape. TMR, the box on
the side of the teletype paper tape punch was commonlny called the chad box.

I wonder if "chad" had origins with teletypes and paper tape, an industry
(telephone) separate from the punched card / data processing industry way
back
when, and in which different terminology developed.




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