IBM SCSI Adapters
MCA Signal Comparison Chart

Based on information from Peter H. Wendt.


Here's a comparison chart of MCA signals used by the different IBM SCSI adapters. The old uncached adapter is a 16-bit card, despite it having the physical 32-bit MCA extension. It's capable of detecting the type of the slot it's plug into. The later cached adapter does not use Address Parity (APAR) as the old did (or has at least had the option for it).

Pin Signal A B C Pin Signal A B C
B01 AUDIO G - - - A01 -CD SETUP X X X
B02 AUDIO - - - A02  MADE 24 X X X
B03 GND X X X A03 GND X X X
B04 14.3MHz - - - A04 A11 X X X
B05 GND X X X A05 A10 X X X
B06 A23 X X X A06 A09 X X X
B07 A22 X X X A07 +5VDC X X X
B08 A21 X X X A08 A08 X X X
B09 GND X X X A09 A07 X X X
B10 A20 X X X A10 A06 X X X
B11 A19 X X X A11 +5VDC X X X
B12 A18 X X X A12 A05 X X X
B13 GND X X X A13 A04 X X X
B14 A17 X X X A14 A03 X X X
B15 A16 X X X A15 +5VDC X X X
B16 A15 X X X A16 A02 X X X
B17 GND X X X A17 A01 X X X
B18 A14 X X X A18 A00 X X X
B19 A13 X X X A19 +12VDC - - -
B20 A12 X X X A20 -ADL X X X
B21 GND X X X A21 -PREEMPT X X X
B22 -IRQ09 - - - A22 -BURST X X X
B23 -IRQ03 - - - A23 -12VDC - - -
B24 -IRQ04 - - - A24 ARB00 X X X
B25 GND X X X A25 ARB01 X X X
B26 -IRQ05 - - - A26 ARB02 X X X
B27 -IRQ06 - - - A27 -12VDC - - -
B28 -IRQ07 - - - A28 ARB03 X X X
B29 GND X X X A29 ARB/-GNT X X X
B30 -DAPAREN X - - A30 -TC - - -
B31 DPAR(0) X - - A31 +5VDC X X X
B32 -CHCK X X X A32 -SO X X X
B33 GND X X X A33 -S1 X X X
B34 -CMD X X X A34 M/-IO X X X
B35 CHRDYRTN X X X A35 +12VDC - - -
B36 -CDSFDBK X X X A36 CDCHRDY X X X
B37 GND X X X A37 D00 X X X
B38 D01 X X X A38 D02 X X X
B39 D03 X X X A39 +5VDC X X X
B40 D04 X X X A40 D05 X X X
B41 GND X X X A41 D06 X X X
B42 CHRESET X X X A42 D07 X X X
B43 -SDSTROBE - - - A43 GND X X X
B44 -SDR(0) - - - A44 -DS16RTN X X X
B45 GND X X X A45 -REFRESH X X X
B46 KEY       A46 KEY      
B47 KEY       A47 KEY      
B48 D08 X X X A48 +5VDC X X X
B49 D09 X X X A49 D10 X X X
B50 GND X X X A50 D11 X X X
B51 D12 X X X A51 D13 X X X
B52 D14 X X X A52 +12VDC - - -
B53 D15 X X X A53 DPAR(1) X - -
B54 GND X X X A54 -SBHE X X X
B55 -IRQ10 - - - A55 -CDDS16 X X X
B56 -IRQ11 - - - A56 +5VDC X X X
B57 -IRQ12 - - - A57 -IRQ14 X X X
B58 GND X X X A58 -IRQ15 - - -
B59 KEY       A59 KEY      
B60 KEY       A60 KEY      
B61 -SDR(1) - - - A61 GND X X X
B62 -MSDR - - - A62 RESERVED - - X
B63 GND X X X A63 RESERVED - - X
B64 D16 - X X A64 -SFDBKRTN - - X
B65 D17 - X X A65 +12VDC - X X
B66 D18 - X X A66 D19 - X X
B67 GND X X X A67 D20 - X X
B68 D22 - X X A68 D21 - X X
B69 D23 - X X A69 +5VDC X X X
B70 DPAR(2) - - - A70 D24 - X X
B71 GND X X X A71 D25 - X X
B72 D27 - X X A72 D26 - X X
B73 D28 - X X A73 +5VDC X X X
B74 D29 - X X A74 D30 - X X
B75 GND X X X A75 D31 - X X
B76 -BE0 - X X A76 DPAR(3) - - -
B77 -BE1 - X X A77 +12VDC X - X
B78 -BE2 - X X A78 -BE3 - X X
B79 GND X X X A79 -DS32RTN - X X
B80 TR32 - X X A80 -CDDS32 - - X
B81 A24 X X X A81 +5VDC X X X
B82 A25 X X X A82 A26 X X X
B83 GND X X X A83 A27 X X X
B84 A29 X X X A84 A28 X X X
B85 A30 X X X A85 +5VDC X X X
B86 A31 X X X A86 -APAREN X X -
B87 GND X X X A87 APAR(0) X X -
B88 APAR(2) X X - A88 APAR(1) X X -
B89 APAR(3) X X - A89 GND X X X

SCSI-A = IBM FRU 15F6561 (20 & 25 MHz osc), 85F0002 (12.5 & 20 MHz osc)
SCSI-B = IBM FRU 85F0000 (SCSI w. Cache / Old)
SCSI-C = IBM FRU 85F0063 (SCSI w. Cache / New)

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