COIM Modification

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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:

  1. Remove 5 caps on the back closest to SIMM contacts
  2. Remove the 0 Ohm resistor above U8 silkscreen
  3. Remove 3 caps on front closest to SIMM contacts
  4. Move 4, 0 Ohm resistors on front closer to SIMM contacts
  5. Install a jumper on the back from pin 34 to second pad above silkscreen "U7". This should be Pin 1 of the chips.
  6. Depending on if this is a conventional or InteliRepeater SIMM install jumpers as follows
    1. If Conventional install jumpers from 80,79,75,74,73
    2. If IR SIMM install jumpers from 80,79,76
  7. 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.

ATAC conversion

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.


JEDEC Flash SIMM Standard