I found this website some years ago, before purchasing my Festo device. Recently I stumbled again on this link. In the 6100 PDFs there are poor b&w photos of an Intercept Jr and/or Intercept I/II but I think I never found an Intercept III. And I think I never found this by a Google search.
Next to the great photo there are also some (new) PDF manuals on the left. The Intercept III has a control panel although the chip works without one.
There’s also a dump/ listing of the ROM in the PDFs. There’s very few 6100 code on the web.
Interesting is the vector address at 7777.
7777 5776 JMP I 7776
7776 7400 Start
The start address is not the vector itself but at 7777 is an instruction, an indexed jump to 7776 and there’s the start vector, which is 7400. So the start is there and not at 5776.
I found it elsewehere, I think in the DecMate II disassembly. I wonder when the vector is at 7777 and when that is used as instruction. Maybe just for JMP and I think for two’s complement negative jump values like 7775. I have at 7777: 0600. PAL says AND I P07600, where P is a pointer to 7600 (600 at current page starting at 7600, so 7600 itself (or the value there?)).
The ROM pairs 5-1, 6-2,… has the same values as in 7-3, 8-4, but just at other addresses. So that is also plausible.
The Intercept Jr. I mentioned here