9 May
2017
9 May
'17
8:14 a.m.
The BSPs for Data Set 101C
Identification and Operation March 1963 (Issue 2)
Test and Installation Methods May 1967
Locating Trouble and Test Procedures 1964
http://www.samhallas.co.uk/repository/telegraph/data_set_101c.pdf
Answers the questions about the relays
-pete
On Tue, May 9, 2017 at 7:57 AM, Pete Lancashire <pete at petelancashire.com>
wrote:
Wikipedia is wrong a lot of times. Usually in the
details.
Modem or MOdulator DEModulator had to come about when one could finally
put a modulator (voltage or current loop) in and get a modulated signal
out, and the reverse, and thirdly all the control circuitry to automate
things.
Long before that, each function was separate.
I can find 1958 and SAGE but non have any proof, and many references are
circular.
On Tue, May 9, 2017 at 7:39 AM, Paul Koning <paulkoning at comcast.net>
wrote:
So Wikipedia is wrong, since it claims that it
was introduced in 1958 for
ASCII and 110 Baud.
Then again, 101/103 modem modulation doesn't care about speed (it isn't
clocked) up to a limit of 300 baud or so.
I wonder if there is also terminology here: what we now call a "modem"
was earlier called a "tuning unit" and that term goes back to 5 bit
machines and the 1950s. It may be more a radio TTY term than a landline
term, but the concept is identical. I remember QST articles around 1958 or
so about RTTY tuning units, built out of tubes with a relay (differential
relay?) thrown in for good measure.
paul
On May 9, 2017, at 10:32 AM, Pete Lancashire
<pete at petelancashire.com>
wrote:
The C version came later with the introduction of ASCII ( 5 to 8 bits )
and 110
baud. So it does not go back to the 50's.
I do not know when the C version was released. The ASCII Teletype Model
35 was
introduced in 1961.
-pete
On Tue, May 9, 2017 at 6:47 AM, Paul Koning <paulkoning at comcast.net>
wrote:
> On May 8, 2017, at 10:27 PM, Pete Lancashire via cctalk <
cctalk at
classiccmp.org> wrote:
Interesting. Released in 1958 but that unit is stamped 10 years later.
It would be nice to see photos of the circuit boards. And I sure
wonder what
those rows of large relays are for.
paul