Obscure 41 Module - FAC/WC

[Ángel Martin]

I just got a 41 module that seems to be peculiar enough / even if it's only because of its capacity.

It's the "Forward Air Controller / Wind Correction" (FAC/W). It appears to have 16k of ROM, a little unusual for a single module of the old generation - possibly a Zeprom??

Does anybody have any information on this peculiar little thing? Needless to say I have no manual or any overlay (if any existed). I suposse I should get a hex dump (disassembly) of the three bottom pages. It does have an automatic key assignment upon CALC_ON vector though.

Best,
AM

[Dan Grelinger]

I've looked at one of those. It is not a ZEPROM. It is a CMT-10, (16K version) and is reprogramable, with the right equipment and software.

[Ángel Martin]

Thanks for the info, Dan. This ROM has some interesting aspects to it, starting with the 16k configuration. Only the first (lowest) page has a proper FAT to it, while the next two have a single "DUMMY" function on their FAT's - and none for the highest one.

I suppose they must be holding table-like data, shame they didn't implement a bank-switched configuration to save address space.

Best,
ÁM

[Dan Grelinger]

The ZEPROM was a much better design, I think it was introduced after the CMT-10. The CMT-10 came in a 16K bank-switched version, too (called the 16B). As far as I know, the two different CMT 16K versions were fixed from the factory, either bank-switched or not, and could not be changed in the field.

There are other modules that have a FAT only in the lower page. One that HP produced was the navigation module. I think the Real Estate module was another HP rom that was 8K and had no rom header in the second page.