Anyone ever seen or used an E&L Instruments IF-100 TRS-80 Interface Box?

Posted by dahousemon@reddit | vintagecomputing | View on Reddit | 6 comments

Found this while going through my father's vintage electronics. It's an educational prototyping board made by E&L Instruments (Derby, CT), designed by the Blacksburg Group, copyright 1979. It connects to the TRS-80 via the card-edge connector and breaks out the data bus, address bus, and control signals to ZIF socket headers. Has a full breadboard, banana jacks, DIP switches, LEDs, and a nice complement of TTL — DM74154N decoder, 74LS20N, and NEC 8216 bus drivers.

I've done a fair amount of searching and this thing is basically a ghost online. No listings, no sold comps, almost zero documentation. I know it was a companion to the TRS-80 Interfacing books by Jonathan Titus, but beyond that I'm coming up empty.

A few things I'm hoping someone here might know:

- How many of these were actually made/sold?

- Were these primarily used in university labs or did hobbyists buy them too?

- Does anyone have the original manual or documentation?

- Has anyone seen another one of these in the wild?

- Any idea what one might be worth to a collector?

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cectech3031@reddit

Just saw one on eBay 10 minutes ago and bought it. This was the first time I saw something like this. Yes, it was used on the Radio Shack TRS-80 computer and with the peek and poke instructions in basic you can make custom interfaces or, like I’m going to use it for, test gear for a Univac logic board tester. Yes, it’s a great price at $271.00.

dahousemon@reddit (OP)

Thank you for this info. That is really helpful.