9 May
2017
9 May
'17
7:49 p.m.
> 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:
>>
>> 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
<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 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.