these RTL or what?

Roy J. Tellason rtellason at
Thu Oct 4 00:38:08 CDT 2007

On Tuesday 02 October 2007 09:56, Allison wrote:
> >Subject: these RTL or what?
> >   From: "Roy J. Tellason" <rtellason at>
> >   Date: Tue, 02 Oct 2007 02:01:29 -0400
> >     To: "General Discussion: On-Topic and Off-Topic Posts"
> > <cctalk at>
> >
> >I ran across some data in the pile of what I've been collecting,  and
> > there's some stuff there apparently by Signetics (?) referring to what
> > they're calling "Utilogic II" -- is this stuff RTL or what?  It doesn't
> > say.  Dates are in the late 1960s,  and it looks like it,  but I figured
> > I'd ask in here...
> There are many early families of saturated logic RTL is the oldest,

Which explains why I was seeing it first,  and hobby-type projects based on it 
back when.

> DTL and it's kin "utilogic" where the intermediate sorta TTL like
> and later TTL( H,LS,S,F,AS,C,HC,HCT flavors).

My first TTL book (which I still have) was a TI book that covered the 
standard, H, and L varieties.  LS and S I can understand,  F and AS still 
confuse me a bit,  I'm not quite sure where they fit in.  Then there are all 
those CMOS variants.  C parts are pretty uncommon these days,  and I'm not 
real clear on the distinction between HC and AC (I know about the ones with T 
in there,  just shifted thresholds on the inputs and I have a pile of 'em.)

> In the middle of all that was ECL (also about three or four generations) a
> fast non saturating logic.

I've read some ECL data,  but have never done a darn thing with it,  nor even 
seen much of anything that used it.  From what I understand it had some weird 
packaging sometimes,  very tight board layout requirements (I was mostly 
thinking of wire-wrapping stuff),  and was very power-hungry.  I guess if I 
ever want a prescaler for a counter to get *way* up there or maybe one or two 
other apps I can think of I might eventually have to go there,  depending on 
what parts I can find.  But I'm in no hurry.  :-)

> What amazing is when people say "60s" you must do so with care as
> 1960 was basically germainium transistors but by 1964 silicon
> transistors are about and ICs were already appearing.  Most
> integrated circuit logic was post '65 and even then from that
> point speeds went from about 3mhz to 30mhz and RTL was replaced
> by TTL by 1970.

I did say "late 1960s" up there.  :-)

> The evoloutionary scale was very steep from the mid 50s to the mid 70s. 
> That 20 years window we went from computers with tubes to microprocessors,
> delays lines or other serial storage to semiconductor RAM.

I remember seeing some of the boards from the tube stuff for sale in various 
electronic junk places around.  I may have even got one or two for parts,  
though there was nothing to be done with those backplane connectors.  I 
remember one set of 9-pin sockets for which it was apparent to me that they 
were using something like a 12AU7,  because of the center-tapped heater 
connections.  :-)

Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin

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