Note: This information comes directly from Stephen J. Friedl, and is a mirror of a page at his website, unixwiz.net.
Each 3B2 board (I/O, backplane, motherboard, etc) has a “CM” code on it that reveals its identity, and we’ve collected many of these codes over the years. Additions welcome.
When taking an inventory of your cards, also note the “AM” number found near the CM code. This is “ArtMaster”, and it’s a board revision: generally higher AM numbers are newer and better.
| Boardcode | Type of card |
|---|---|
| CM190A | 3B2/300 system board |
| CM191A | 1/4 MB RAM card (/300) |
| CM191B | 1 MB RAM card (/300 /310 /400) |
| CM191C | 1 MB RAM card (/300 /310 /400) |
| CM191D | 2 MB RAM card, 1/2 height (/300 /310 /400) |
| CM192B | 2 MB RAM card (/400) |
| CM193A | 3B2/300 backplane |
| CM193B | 3B2/300 and /310 backplane |
| CM194B | 3B2/400 backplane |
| CM195A | NI (10Mb Ethernet) |
| CM195AA | AIC card (Alarm Interface Circuit) |
| CM195AC | Datakit Board |
| CM195AD | Datakit Board |
| CM195AE | Gen. Purpose Synchronous Controller |
| CM195AY | EPORTS (8 serial) |
| CM195B | PORTS (4 serial + 1 parallel) |
| CM195BA | HPP PORTS (4 serial + 1 parallel) |
| CM195H | CTC (23MB Cartridge Tape Controller) |
| CM195K | XDC (Expansion Disk Controller) |
| CM195T | ISC (Intelligent Serial Controller) |
| CM195U | NAU (StarLAN) |
| CM195W | SCSI controller |
| CM195Y | EPORTS card (8 serial) |
| CM518A | 3B2/500+/600 system board (WE32100 @ 18 MHz) |
| CM518B | 3B2/622 system board (WE32200 @ 22 MHz) |
| CM518C | 3B2/1000 M80 system board (WE32200 @ 24 MHz w/ 2 MMUs) |
| CM519A | 3B2/600 backplane |
| CM519B | 3B2/1000 M80 backplane |
| CM520A | 3B2/500 backplane |
| CM521A | differential SCSI controller (ver 3 hardware only) |
| CM522A | VCACHE card - only used with CM518A and CM518B |
| CM523A | 4 MB RAM card (3B2/600, /600) – 256 kbit chips |
| CM523AA | 4 MB RAM card (3B2/500, /600) – 1 Mbit chips |
| CM523B | 2 MB ECC RAM card (V3) |
| CM523D | 16 MB RAM |
| CM524A | PE card (multiprocessor) - goes in PBus slot |
| CM527A | MPB card (multiprocessor) - goes in BUB slot |