HP7202A Schematics questions

Ashley Carder wacarder at earthlink.net
Fri Jun 29 09:52:04 CDT 2007

>The interface has a 15 pin male adapter, with 
>8 pins on top and 7 on bottom.
>I have added a link to the schematics at the bottom of
>the HP7202A Plotter page on my web site.  
>Go to:
>and click on the link at the bottom of the page.

Can someone help me understand these old HP schematics?
I see the 15 adapter pins shown at the top right of the
page, and see where one of the pins (# 5) appears to go
to something labeled EIA IN on the "Logic Mother Board"
section.  Some pins (3, 4, and 6) appear to not be 
connected to anything.  Most of the others seem to go 
to the Analog Mother Board, but I am not sure how to 
follow them from there.  What would be nice is if I 
could get enough of an understanding from this schematic 
to figure out how to construct both a 20mA adapter and 
an EIA (RS232) adapter,  or an adapter that has the 15
pin connector on one end, and two connectors on the
other end (one for 20mA and one for EIA).


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