>> 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
>> 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 2017-May-09, at 7:39 AM, Paul Koning via cctalk 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 If my recollection and interpretation of the limited tech description available is correct, SIGSALY was doing frequency-domain-multi-channel, FSK-digital-transmission during WWII, that is, sending multiple digital bit streams over a radio channel. (Along with a host of other amazing technical achievements for the time, including or esp. in the digital realm). I haven't looked into whether RTTY was prior to that, or post-war, or whether RTTY may have got some of the ideas from SIGSALY.
