HP board id?

Marc Verdiell marc.verdiell at gmail.com
Thu May 14 16:21:24 CDT 2015

Thanks a million! I did not know that. As for the receivers, it can go into
straight TTL apparently, I read that somewhere in an HP manual.

>From: "J. David Bryan" <jdbryan at acm.org>
>> ...where to get the older CTuL logic IC bus drivers (the 9956 in
>> particular) besides from old boards? 

>With the inclusion of a pulldown resistor to -2V, the TI SN75121 is a
recommended replacement, per page 5-6 of the 
>"HP 1000 M/E/F-Series Computers I/O Interfacing Guide" (02109-90006
September 1980).  It's an active part:
> http://www.ti.com/product/sn75121
>                                      -- Dave

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