[GreenKeys] So what else can I do with this?

[John Nagle]

On 04/04/2016 06:10 PM, drlegendre . wrote:

> Now I have a question about the whole auto-start thing. I don't see that
> my M15 (ex-Bell) has any sort of motor control relay installed. So how
> is that normally handled? Is the relay an internal / external accessory
> or option provided by Teletype Co. or something else? I see that the
> Aetheric design does allow for a control relay, but a Solid-State
> device, in that case.
>
> So how do I implement the auto-start function? Do I re-wire my M15 to
> incorporate a SS relay, or do I need some old, original parts to make
> this work? I do have what I think is an appropriate SS relay, for what
> that's worth..

   I just used a standard solid-state relay, because you can
drive those from a +5 logic level or an RS-232 signal.
It's connected to one of the RS-232 control lines (RTS, Request
to Send) which you can turn on from the computer side.

   On my control box, the power outlet for the Teletype is controlled
by that solid state relay.  The Teletype's wiring is completely
stock, except that I put a new 3-wire cord with ground and
standard 120VAC plug on all my machines.

   The control box

     http://www.aetherltd.com/aesthetic.html

has a USB to serial converter, the serial to current loop board,
a 120VDC power supply, the solid state relay for the motor control,
a GFCI outlet device protecting against ground faults, a 5A
circuit breaker, a meter, big indicator lamps, and a big black
button which does a BREAK.  That's all it does; there's no computer
in there.  Input is a USB port.

The "baudotrss" software manages startup and shutdown. There are
delays on both startup and shutdown. At startup, time is allowed
for the motor to come up to speed, and at shutdown, time is allowed
for all remaining characters in the queue to print.

The Teletype system turned on the motor on any MARK to SPACE
transition, and turned it off on receipt of a STOP (FIGS-H).
This option isn't standard USTTY or ITA-2, but apparently
was once orderable.  I've seen this in documents, but don't
have any machines with the feature.

				John Nagle