The Motorola Console Operator Interface Module (COIM) uses a 18 bit wide (0x40000) bus address bus supporting 4 256kb flash chips. The Quantar/ATAC uses a 19 bit wide address bus (0x80000) for 512k flash chips. The chips are almost identical so the board only needs a few simple modifications.
The modification is easy:
- Remove 5 caps on the back closest to SIMM contacts
- Remove the 0 Ohm resistor above U8 silkscreen
- Remove 3 caps on front closest to SIMM contacts
- Move 4, 0 Ohm resistors on front closer to SIMM contacts
- Install a jumper on the back from pin 34 to second pad above silkscreen "U7". This should be Pin 1 of the chips.
- Depending on if this is a conventional or InteliRepeater SIMM install jumpers as follows
- If Conventional install jumpers from 80,79,75,74,73
- If IR SIMM install jumpers from 80,79,76
- Install the proper 29F040B-90 PLCC Flash memory chips and program. The Conventional SIMM only needs U1-U4 populated
The COIM SIMM is available from Motorola for about $40, Part number BLN7062D.
There are programmed SIMMs being sold on eBay as of December 2015 for $75.
This is the same as above, but setup for 4 Megabit by 8 devices. This is only pin 76 brought low/ground.
Note the ATAC does care about this being set.
If converting to a ATAC 3000, Only the first bank is needed. The 9600 needs both banks.