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 <p...@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 <paulkon...@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 <p...@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 <paulkon...@comcast.net> >> wrote: >> > >> > > On May 8, 2017, at 10:27 PM, Pete Lancashire via cctalk < >> cctalk@classiccmp.org> wrote: >> > > >> > > Bell 101C >> > > >> > > https://goo.gl/photos/hrhAwvzMBLWWteXu6 >> > > >> > > https://en.wikipedia.org/wiki/Bell_101 >> > >> > 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 >> > >> > >> > >> > >> >> >> >
