HP board id?
J. David Bryan
jdbryan at acm.org
Thu May 14 21:52:00 CDT 2015
On Thursday, May 14, 2015 at 14:21, Marc Verdiell wrote:
> Thanks a million!
> As for the receivers, it can go into straight TTL apparently, I read
> that somewhere in an HP manual.
Both TTL and LSTTL (but not STTL or HTTL) will work with an appropriate
pulldown resistor. LSTTL is recommended for the lower power and improved
speed over TTL. The pulldowns are necessary to guarantee logic zeros when
driven by the original CTuL or newer 75121 parts, which have open-emitter
Section 5-7, "Computer Backplane Assembly Requirements," of the
aforementioned interfacing manual details the recommended circuits.
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