HP2100A luser questions

tony duell ard at p850ug1.demon.co.uk
Thu Nov 20 23:33:25 CST 2014

> On Wed, Nov 19, 2014 at 2:43 PM, tony duell <ard at p850ug1.demon.co.uk> wrote:
> > What is Current Transfer Logic, the machine seems to be full of such ICs?  Any data sheets,
. > etc out there?

> I don't know about Current Transfer Logic, but my vague recollection
> (probably wrong) was that it used Signetics Utilogic II and Fairchild
> CuL or CTuL families. There are three different years' Utilogic
> databooks on Bitsavers. There is some data on CuL and CTuL in the 1969
> Fairchild Data Catalog on Bitsavers.

Yes, you're right. It's CTuL. The HP parts lists in the manuals call them 'CTL', I foolishly 
looked that up on Google and got a translation to 'Current Transfer Logic'. No, it's
'Complementary Transistor microLogic', which seems to be somewhat ECL-like.

The HP2100A and the interfaces I have seem to be a mixture of CTuL and normal 
TTL parts. I assume the former are unobtainium now, let's just hope that's not
where any faults are.

I will take a look at the Fairchild book on bitsavers, thanks...


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