MCA 116 pin FEMALE connector
Micro Channel Architecture (MCA) was IBM’s proprietary 16- or 32-bit expansion bus, introduced in 1987 with the PS/2 line and also used in RS/6000, AS/400 and some System/370 machines. Designed to replace the ISA (PC/AT) bus, it added bus mastering with arbitration, level-triggered shareable interrupts, software-driven configuration (Programmable Option Select, an ancestor of plug-and-play) and improved grounding. Its proprietary, licence-fee model limited adoption, and it was eventually displaced by EISA and PCI. This 16-bit variant uses a 116-contact card-edge connector.
| PIN | SIGNAL | PIN | SIGNAL |
|---|---|---|---|
| B01 | AUDIO GND | A01 | -CD SETUP |
| B02 | AUDIO | A02 | MADE 24 |
| B03 | GND | A03 | GND |
| B04 | 14.3 MHz OSZ | A04 | A11 |
| B05 | GND | A05 | A10 |
| B06 | A23 | A06 | A09 |
| B07 | A22 | A07 | +5 Vdc |
| B08 | A21 | A08 | A08 |
| B09 | GND | A09 | A07 |
| B10 | A20 | A10 | A06 |
| B11 | A19 | A11 | +5 Vdc |
| B12 | A18 | A12 | A05 |
| B13 | GND | A13 | A04 |
| B14 | A17 | A14 | A03 |
| B15 | A16 | A15 | +5 Vdc |
| B16 | A15 | A16 | A02 |
| B17 | GND | A17 | A01 |
| B18 | A14 | A18 | A00 |
| B19 | A13 | A19 | +12 Vdc |
| B20 | A12 | A20 | -ADL |
| B21 | GND | A21 | -PREEMPT |
| B22 | -IRQ 09 | A22 | -BURST |
| B23 | -IRQ 03 | A23 | -12 Vdc |
| B24 | -IRQ 04 | A24 | ARB 00 |
| B25 | GND | A25 | -ARB 01 |
| B26 | -IRQ 05 | A26 | ARB 02 |
| B27 | -IRQ 06 | A27 | -12 Vdc |
| B28 | -IRQ 07 | A28 | ARB 03 |
| B29 | GND | A29 | ARB/-GNT |
| B30 | -DPAREN | A30 | -TC |
| B31 | DPAR(0) | A31 | +5 Vdc |
| B32 | -CHCK | A32 | -SO |
| B33 | GND | A33 | -S1 |
| B34 | -CMD | A34 | M/-IO |
| B35 | CHRDYRTN | A35 | +12 Vdc |
| B36 | -CD SFD | A36 | CD CHRDY |
| B37 | GND | A37 | D 0 |
| B38 | D 01 | A38 | D 02 |
| B39 | D 03 | A39 | +5 Vdc |
| B40 | D 04 | A40 | D 05 |
| B41 | GND | A41 | D 06 |
| B42 | CHRESET | A42 | D 07 |
| B43 | -SD STROBE | A43 | GND |
| B44 | -SDR (0) | A44 | -DS 16 RTN |
| B45 | GND | A45 | -REFRESH |
| B46 | - key - | A46 | - key - |
| B47 | - key - | A47 | - key - |
| B48 | D 08 | A48 | +5 Vdc |
| B49 | D 09 | A49 | D 10 |
| B50 | GND | A50 | D 11 |
| B51 | D 12 | A51 | D 13 |
| B52 | D 14 | A52 | +12 Vdc |
| B53 | D 15 | A53 | DPAR(1) |
| B54 | GND | A54 | -SBHE |
| B55 | -IRQ 10 | A55 | -CD DS 16 |
| B56 | -IRQ 11 | A56 | +5 Vdc |
| B57 | -IRQ 12 | A57 | -IRQ 14 |
| B58 | GND | A58 | -IRQ 15 |
| B59 | reserved | A59 | reserved |
| B60 | reserved | A60 | reserved |