[GreenKeys] Information on Electronic Systems, San Jose, CA ?

[Ralph Irish]

GreenKeyers

In doing some much needed cleaning up around here, I stumbled upon a couple of interesting, small
circuit boards.  They were sold by the Electronic Systems company of San Jose, California in the
late 1970s.  One of the two items shows a different mailing address in Burlingame, CA.  Same
phone number on each package.

One board measures 1 5/8" x 1 1/2" (plus a bit more for an edge connector, 10 contact)
It is described as a "TTL & RS-232 Interface"   It has an IC, a transistor and 10 more
parts.

It's description reads:

"The RS-232 board has two separate circuits.  One converts RS-232 to TTL.  The
other converts TTL to RS-232.  The board has a ten pin edge connector.  Power
required is +12 and -12 volts."  (Copyright © 1977)

The other board measures 2 1/2" x 1/2" with no edge connector.  It is also described
as a "TTL and RS-232 Interface"  It has a transistor and six other parts.

It's decription reads:

"This board has two separate circuits.  One converts RS-232 to a 20 mA current
loop.  The other converts a 20 mA loop to RS-232."  (Copyright © 1978)

It has four mounting holes in the corners and 11 holes drilled for soldering wires.
I am truly puzzled why this was not also offered with an edge connector:  3 of the
11 connection points are "GND" and solid lines drawn between them on the diagram.

The diagram shows "TO TTY PRINTER" at one point, and "FROM TTY KEYBOARD" at another
point.

It also requires +12 and -12 Volts.

I don't know if the company is still around or not.  Silicon Valley companies came
and went, often with little fanfare.  I did a quick search on the name and found a
company in San Jose with a similar name, but their website did not indicate much 
in the line of electronic products.  The phone number on the package now shows to
what appears to be a private residence.

- - - -

If there is any interest in either of these items, I can make the circuits available.
I can attempt to 'scan' the foil side of the boards.  This might make it easy for
someone to make up circuit boards.

One or the other might allow quick and simple interconnects for those using Model
32 and 33 Teletypes.

I have long since forgotten where I originally saw them advertised.

Please let me know off list if there is any interest.

If anyone cares to do additional research, the name and addresses of the company are:

Electronic Systems
P.O. Box 212
Burlingame, CA  94010
(408)  374-5984

for the second board:

Electronic Systems
P.O. Box 9641
San Jose, CA  95157
(408)  374-5984

Thanks,

Ralph - W8ROI


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