110 Baud modem

[Pete Lancashire]

Once you convert from Bell to English things make a bit more sense. One has
to have a understanding of analog engineering terms but this oldie pretty
much works the same as any Hayes etc modems.

The Modulator takes digital 1/0 levels and converts to one of two sine wave
frequencies.

The Limiter, Discriminator take from the sender the analog waveform (pretty
much sine wave) and limits the amplitude and the  discriminator decides if
the frequency is a 1 or 0. The hybrid does impedance matching, echo
cancellation etc.

Many of the terminal block connections are for setting signal levels, later
this was done with circuitry, but was
too complex for doing in individual transistors, or at least in the space
available.

The Restrainer is filter looking for a particular frequency and when one
comes down the line from the CO, it basically is a slow down signal.

Timer - timing

Send Break timer - think Signetics 555.

I've not seen a clear breakdown of the relays

AN (AK?) - Answer
CON - Connected
M - Momentarily hold
OR - Originate vs Receive (controls the frequencies etc)
S
RU
CY
RB
RS





On Tue, May 9, 2017 at 9:06 AM, Chuck Guzis via cctalk <
cctalk at classiccmp.org> wrote:

> Looking at this documents:
>
> http://www.samhallas.co.uk/repository/telegraph/data_set_101c.pdf
>
> I sill can't figure out what a lot of the stuff inside is for.
>
> --Chuck
>
>
>