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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets.

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Old 7th Apr 2021, 10:11 am   #21
Wendymott's Avatar
Join Date: Jun 2013
Location: Huddersfield, West Yorkshire, UK.
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Default Re: DTL logic. I've finally seen some.

Umpteen years ago Keithley Lifts used Nor Bits (DTL) in their logic controllers...They made a donation to the Otley Radio Society when they became obsolete, I guess they went onto TTL . We had so many modules it was embarrassing to know what to do with them but some of the members embraced them. At that time I was too wrapped up in RF, to appreciate their value.
Should get out more.

Wendy G8BZY
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Old 7th Apr 2021, 11:41 am   #22
Join Date: Nov 2015
Location: Maidstone, Kent, UK.
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Default Re: DTL logic. I've finally seen some.

Re references to Elliott made logic; RTL was used first as discrete component units followed by Minilog as encapsulated modules. This was followed rapidly by discrete component DTL on early "DZ" boards and then integrated DTL in dil and flat packs using the 94n range from Fairchild, TI etc also on DZ mother boards. A range of flat pack modules were also used briefly prior to TTL LSI and were designed for use in wire wrap assemblies. This then evolved into the use of TTL in dil packaging. The one logic type promoted by SGS Fairchild that rarely featured was Ctul which was fast and I believe used a lower voltage. The main driver for the transition from RTL to DTL was the requirement for speed and military environment. Examples of all these units exist in equipment at Bletchley Park.

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Old 7th Apr 2021, 1:20 pm   #23
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Default Re: DTL logic. I've finally seen some.

We were using the gold plated military flat packs for our custom design ICs in an application where space was restricted and operation over an extended ambient temperature range was a requirement. The empty 14 pin type cost around 5 each in 1973 pounds. We also used 10 pin and 22 pin types.
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Old 7th Apr 2021, 8:07 pm   #24
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Default Re: DTL logic. I've finally seen some.

Talking of Elliott Minilog modules, the first mainframe computer I encountered was an Elliott 803 whilst I was at university. I seem to remember an abundance of Minilog modules in it.
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Old 7th Apr 2021, 8:11 pm   #25
Join Date: Sep 2018
Location: Maldon, Essex, UK.
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Default Re: DTL logic. I've finally seen some.

Originally Posted by Diabolical Artificer View Post
Seeing "Elliott Automation" mentioned has reminded me that I offered a load of mainly DTL - based sub-assemblies , built on those very useful Elliott DZCU and DZCK p.c.b.s , in the Parts Offered section, on March 17th.. Not even a hint of interest , and now EVERYONE's talking about DTL
It's one thing to chat about DTL another to have an application for said boards.
Very true , Andy , as with many other technologies of years ago !
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Old 8th Apr 2021, 9:02 am   #26
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Location: Near Thame, Oxfordshire.
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Default Re: DTL logic. I've finally seen some.

I had some of the Norbit Series 1 devices in the late 60's, some flops and gates. They came in red, orange and yellow packages; of course I had to break one open to see what was in them and they had a small PCB maybe 2"x1" with discrete transistors/resistors etc. I have a feeling they were an uncommon type - OC42? OC47?

There was a Mullard or Philips apps note that described their uses including using a wire delay line for serial memory storage.
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