[GreenKeys] Interface board for Model 15, schematic and partslist (ROversion)

[Lester Veenstra]

Bingo !

 That’s what I had in mind.   Now stored away for use on my return to
civilization (2-3 years) and the work shop full of R-390's, mod 28/32/33s.
Do wish I still had my original 15 page printer though.   Will have to look
out for one that is headed for a dump, at that time.

 
Lester B Veenstra  MØYCM K1YCM
lester at veenstras.com
m0ycm at veenstras.com
k1ycm at veenstras.com
 
 
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-----Original Message-----
From: gil at baudot.net [mailto:gil at baudot.net] 
Sent: Saturday, February 14, 2009 11:44 PM
To: lester at veenstras.com
Cc: greenkeys
Subject: RE: [GreenKeys] Interface board for Model 15, schematic and
partslist (ROversion)

> -------- Original Message --------
> Subject: RE: [GreenKeys] Interface board for Model 15,	schematic
and
> partslist (RO version)
> From: "Lester Veenstra" <m0ycm at veenstras.com>
> 
> Not enough power available on even a "spec" RS-232 to generate the 
> needed loop supply for the older machines - which need at least 60V - 
> 90V would be better.


Yeah Les, you can't power a loop, but you can usually draw enough power
from the 232 port for the interface, and key an external loop supply and
limit resistor, as in my old TAP.  This was the smallest loop keyer I
made, squeezed into a DB9 adapter housing:
http://www.baudot.net/gil/tty232-tap/TTY232_TAP.pdf

gil