DTL logic. I've finally seen some. - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

Wendymott · 7th Apr 2021, 11:11 am

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.

Orakle42 · 7th Apr 2021, 12:41 pm

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.

Orakle42.

emeritus · 7th Apr 2021, 2:20 pm

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.

Vintage_RC · 7th Apr 2021, 9:07 pm

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.

Rileyman · 7th Apr 2021, 9:11 pm

Quote:

Originally Posted by Diabolical Artificer

Quote:

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 !

Keith956 · 8th Apr 2021, 10:02 am

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.

7th Apr 2021, 11:11 am	#21
Wendymott Octode Join Date: Jun 2013 Location: Huddersfield, West Yorkshire, UK. Posts: 1,795	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. Regards Wendy G8BZY

7th Apr 2021, 12:41 pm	#22
Orakle42 Pentode Join Date: Nov 2015 Location: Maidstone, Kent, UK. Posts: 131	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. Orakle42.

7th Apr 2021, 2:20 pm	#23
emeritus Dekatron Join Date: Jan 2012 Location: Brentwood, Essex, UK. Posts: 5,339	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.

7th Apr 2021, 9:07 pm	#24
Vintage_RC Heptode Join Date: Sep 2018 Location: Twickenham, London, UK. Posts: 538	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. __________________ Alan G6PUB, BVWS

8th Apr 2021, 10:02 am	#26
Keith956 Heptode Join Date: Jun 2019 Location: Oxfordshire Posts: 738	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.