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Altair 8800 front panel hex display

Never seen anything like that on an Altair before. Could be quite useful, unlike the switch in one picture that faces sideways ;)
 
Those digits can decode hex from the 4 signals directly and display the correct hex value. I've seen some of these type boards for a RC2014 before. I think the displays are still out there, but probably hard to find and pricey. I wondered about making a FPGA type project at one point that emulated the logic of the displays, but never got around to it. I'm sure there are some old IC"s that did the same, but these displays are cool because they have the decoding IC built right in!

This might be the RC2014 thing I was thinking about:

Datasheet for the display:

They are $30 each at Jameco!
 
Those digits can decode hex from the 4 signals directly and display the correct hex value. I've seen some of these type boards for a RC2014 before. I think the displays are still out there, but probably hard to find and pricey. I wondered about making a FPGA type project at one point that emulated the logic of the displays, but never got around to it. I'm sure there are some old IC"s that did the same, but these displays are cool because they have the decoding IC built right in!
The manual including schematic for an S-100 front panel with hex display is at
http://www.s100computers.com/Hardware Folder/Wameco/FPB/FPB.htm
I wonder if it could be useful?
 
Those Hex displays appear to be the common garden Texas Instruments TIL311, these have been around since the 1970's. They are readily available from a number of sellers, I have a box of them:


(interestingly Innocor in Canada once made a low power CMOS version of them. I think I bought the remainder of their stock. In the past I made these into a 12/24 hr up down clock with 4000 series cmos IC's pic attached).

There is a modern replacement for them too : Avago / Broadcom HDSP -0962 bright green, or red hexadecimal displays, super quality displays. I used these in the keyboard diagnostic instrument in this article:



I also once made a 16 bit binary to to decimal converter that used the TIL311's, it had a very short latency of 350nS to do the conversion. I made it because binary was messing with my head for a project and I wanted to immediately see the decimal value. It came out as a handy sort of "logic probe" for other problems too, I made it with a manual or external data latch input so it could capture transient binary values. It was quite power hungry with all the TTL IC's and I had to ventilate the housing with a fan
 

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