PinOuts Galore!

This information came from the comp.sys.ibm FAQ, Mac manuals and Apple Tech Info Library (articles 12934, 9089, and 5493), reference books, an Amiga FAQ, a Sun hardware FAQ, and the HP-48 FAQ. A little bit of this is just plain scavenged, or extracted from a continuity test on a cable! Let me warn you, my interest is in pinouts I can use with my Mac, or my HP48 calculator, or my Solaris box, not in every possible pinout. Do a web search to find more of this kind of information, or check the FAQs. Use this information at your own risk! There are many more pinouts collected by Nick if you want an alternative.

The List of Choices Here

Macintosh

SCSI Connector (Single Ended) DB-25 Female
SCSI Connector Centronics-50 Female
SCSI Connector (Single Ended) IDC-50 (ribbon cable) Male
SCSI Connector (Differential) IDC-50 (ribbon cable) Male
Apple Desktop Bus for keyboard and mouse
Macintosh Serial Connectors for printer and modem
Macintosh-PC Serial Converter
Old-style Macintosh monitor
Audio Jack
10Base-T RJ-45 Male Ethernet
10Base-T Crossover Ethernet
IIcx/IIci/Q700 power supply
Internal Floppy Disk Drive Connector
Floppy Port (very old 68K Macs, IIci and earlier)
30-pin SIMMs (older 68K Macs)
72-pin SIMMs (newer 68K Macs and older PowerMacs)
PCI cards (newer PowerMacs)

HP-48

HP Serial Connector

Sun

PC

Connector Diagrams

These nice diagrams (in mono-spaced font) are mostly from the IBM FAQ again.

4 pin Mini DIN Male    8 pin Mini DIN Male    8 pin Mini DIN Female
  --v--                  ---v---                ---v---
 / 3 4 \                / 6 7 8 \              / 8 7 6 \ 
|  1 2  |              | 3  4  5 |            | 5  4  3 |
 ]  -  [                ]  1 2  [              ]  2 1  [
  -----                  -------                -------

5 pin DIN Male          DB-15 Male                   6 pin Mini DIN Male
    --+--               ----------------------             ---
   /  ^  \              \   1  2  3  4  5    /           ] 2 1 [
  | 1   3 |              \ 6  7  8  9 10    /           | 4   3 |
   \ 425 /                \ 11 12 13 14 15 /             \6   5/
    -----                  ----------------                -^-

DB-9 (DE-9) Male        DB-15 (DA-15) Male 
-------------           -------------------------- 
\ 1 2 3 4 5 /           \ 1  2  3  4  5  6  7  8 /
 \ 6 7 8 9 /             \ 9  10 11 12 13 14 15 /
  ---------               ----------------------

DB-25 Male                           IDC-50 Male 
------------------------------        ------------------- 
\ 1  2  3  4  5  7  8 ... 13 /       | 1  3  5  7 ... 49 |
 \ 14 15 16 17 18 .......25 /        | 2  4  6  8 ... 50 |
  --------------------------          -------------------

(Power Connector) Male                RJ-45 Male
  __________
 /          \                         ------------------ 
| 4  3  2  1 |                        | 8 7 6 5 4 3 2 1 |
 ------------                         -------____-------

DD-50 (Sun ShoeBox SCSI connector)    HP-48 Female 
-------------------------------         _______ 
\  1  4  7 10 13 16 19 ... 49 /        /       \
 \   3  6  9 12 15 18 ... 48 /        | 1 2 3 4 |
  \ 2  5  8 11 14 17 ... 50 /         -----------
   -------------------------

DB-19 Male                          20-pin socket header 
--------------------------------    ---------------____-------------- 
\ 1  2  3  4  5  6  7  8  9 10 /    | 19 17 15 13 11  9  7  5  3  1 |
 \ 11 12 13 14 15 16 17 18 19 /     | 20 18 16 14 12 10  8  6  4  2 |
  ----------------------------      ---------------------------------

30 pin SIMM                         72 pin SIMM 
-------------------------------     --------------------------------------- 
|                             |     |                                     |
 )                            |      )                 _                  |
 --|||||||||||||||||||||||||---      --|||||||||||||||/ \|||||||||||||||---
   1                       30          1             36  37            72

        PCI Cards Universal/3.3V/5V and 32/64 bit.

PCI Universal Card 32/64 bit
 ---------------------------------------------------------------- 
|    PCI         Component Side (side B)                         | 
|                                                                | 
|                                                                | 
|                                                optional        | 
|    ____     mandatory 32-bit pins            64-bit pins  _____| 
|___|    |||||||--|||||||||||||||||--|||||||--||||||||||||||
         ^     ^  ^               ^  ^     ^  ^            ^
       b01   b11  b14           b49  b52 b62  b63          b94

PCI 5V Card 32/64 bit 
|                                                optional        | 
|    ____     mandatory 32-bit pins            64-bit pins  _____| 
|___|    ||||||||||||||||||||||||||--|||||||--||||||||||||||

PCI 3.3V Card 32/64 bit 
|                                                optional        | 
|    ____     mandatory 32-bit pins            64-bit pins  _____| 
|___|    |||||||--||||||||||||||||||||||||||--||||||||||||||

PinOuts

SCSI Connector (Single Ended) DB-25 Female
total length of all cables not to exceed 20 feet (6 meters)

 1  REQ   request             14  GND   signal ground
 2  MSG   message             15  C/D   common/data
 3  I/O   input/output        16  GND   signal ground
 4  RST   SCSI bus reset      17  ATN   attention
 5  ACK   acknowledge         18  GND   signal ground
 6  BSY   busy                19  SEL   select
 7  GND   signal ground       20  DBP   data parity
 8  DB0   data bit 0          21  DB1   data bit 1
 9  GND   signal ground       22  DB2   data bit 2 
10  DB3   data bit 3          23  DB4   data bit 4 
11  DB5   data bit 5          24  GND   signal ground 
12  DB6   data bit 6          25  TPWR  terminator power 
13  DB7   data bit 7

SCSI Connector Centronics-50 Female

26  *Data 0           39  Ground 
27  *Data 1           40  Ground 
28  *Data 2           41  *ATN 
29  *Data 3           42  Ground (Unused?) 
30  *Data 4           43  *BSY 
31  *Data 5           44  *ACK 
32  *Data 6           45  *RST 
33  *Data 7           46  *MSG 
34  *Parity           47  *SEL 
35  Ground            48  *C/D 
36  Ground            49  *REQ 
37  Ground            50  *I/O 
38  Terminator Power

Note:
Pins 1-12 and 14-25 are grounds.

SCSI Connector (Single Ended) IDC-50 Male

pin     assignment|pin  assignment|pin  assignment|pin  assignment 
01      GND       |02     -DB0    |27     GND     |28     GND 
03      GND       |04     -DB1    |29     GND     |30     GND 
05      GND       |06     -DB2    |31     GND     |32     -ATN 
07      GND       |08     -DB3    |33     GND     |34     GND 
09      GND       |10     -DB4    |35     GND     |36     -BSY 
11      GND       |12     -DB5    |37     GND     |38     -ACK 
13      GND       |14     -DB6    |39     GND     |40     -RST 
15      GND       |16     -DB7    |41     GND     |42     -MSG 
17      GND       |18     -DBP    |43     GND     |44     -SEL 
19      GND       |20     GND     |45     GND     |46     -C/D 
21      GND       |22     GND     |47     GND     |48     -REQ 
23      GND       |24     GND     |49     GND     |50     -I/O 
25      (open)    |26     TERMPWR

SCSI Connector (Differential) IDC-50 Male

pin     assignment|pin  assignment|pin  assignment|pin  assignment 
01      (open)    |02     GND     |27     GND     |28     GND 
03      +DB0      |04     -DB0    |29     +ATN    |30     -ATN 
05      +DB1      |06     -DB1    |31     GND     |32     GND 
07      +DB2      |08     -DB2    |33     +BSY    |34     -BSY 
09      +DB3      |10     -DB3    |35     +ACK    |36     -ACK 
11      +DB4      |12     -DB4    |37     +RST    |38     -RST 
13      +DB5      |14     -DB5    |39     +MSG    |40     -MSG 
15      +DB6      |16     -DB6    |41     +SEL    |42     -SEL 
17      +DB7      |18     -DB7    |43     +C/D    |44     -C/D 
19      +DBP      |20     -DBP    |45     +REQ    |46     -REQ 
21      DIFFSENS  |22     GND     |47     +I/O    |48     -I/O 
23      GND       |24     GND     |49     GND     |50     GND 
25      TERMPWR   |26     TERMPWR

Apple Desktop Bus
4-pin mini DIN, total length of all cables not to exceed 16 feet (5 meters)

pin  assignment 
1    ADB    data
2    PWRON  power on
3    +5V    +5VDC
4    GND    signal ground

Mac Modem and Printer Ports
8-pin mini DIN

pin  assignment  description 
1    HSKo        handshake out 
2    HSKi        handshake in, external clock 
3    TXD-        transmit data - 
4    GND         signal ground 
5    RXD-        receive data - 
6    TXD+        transmit data + 
7    GPi         General Purpose input (modem port 2nd ext clk) 
8    RXD+        receive data +

Mac-PC (basic) Serial Converter
8-pin mini DIN (Mac, RS-422) to DB9F (PC, RS-232)

Mac  PC  assignment
1    4   DTR/HSKo
2    7   RTS/HSKi
3    3   TX
4    5   GND
5    2   RX
6    NC
7    NC
8    NC

Old-style Macintosh monitor
DB-15 (two rows, not VGA three rows)

pin  signal       description
 1  RED.GND      red video ground
 2  RED.VID      red video
 3  CYSNC~       composite sync
 4  SENSE0       monitor ID, Bit 1
 5  GRN.VID      green video
 6  GRN.GND      green video ground
 7  SENSE1       monitor ID, Bit 2
 8  NC           no connection
 9  BLU.VID      blue video
10  SENSE2       monitor ID, Bit 3
11  C&VSYNC.GND  CSYNC and VSYNC ground
12  VSYNC~       vertical sync
13  BLU.GND      blue video ground
14  HSYNC.GND    HSYNC ground
15  CHASSIS.GND  chassis ground

This might work as a Mac-to-VGA adapter, but try it first.

Mac DB-15  Signal        VGA HD-15
        2  red video     1
        1  red ground    6
        9  blue video    3
       13  blue ground   8
        5  green video   2
        6  green ground  7
       15  H Sync        13
       12  V Sync        14
       14  Sync ground   10
       10  connect 10
        7  and 7 so sense is VGA

Audio Jack

3.5 mm miniature stereo plug 
(sleeve)  GND    signal ground 
(ring)    RIGHT  1.5V peak-to-peak right audio 
(tip)     LEFT   1.5V peak-to-peak left audio

10Base-T RJ-45 Male Ethernet

pin     assignment      twisted pair    color         position
1       TxData+         2               White/Orange  4
2       TxData-         2               Orange        3
3       RxData+         3               White/Green   6
4          -            1               Blue          1
5          -            1               White/Blue    2
6       RxData-         3               Green         5
7          -            4               White/Brown   8
8          -            4               Brown         7

10Base-T Crossover Ethernet

Connector 1 to  Connector 2 
TxData+         RxData+ 
TxData-         RxData- 
RxData+         TxData+ 
RxData-         TxData-

Macintosh IIcx/IIci and Quadra 700 power supply

Pin Signal   Description
 1  +12V     +12 volts
 2  +5V      +5 volts
 3  +5V      +5 volts
 4  +5V      +5 volts
 5  GND      Ground
 6  GND      Ground
 7  GND      Ground
 8  -12V     -12 volts
 9  /PFW     Power Fail Warning
10  +5V.TRKL Supply voltage for power-on circuit

Internal Floppy Disk Drive Connector
IDC-20 small ribbon cable for SuperDrive

Pin   Signal   Description
  1   GND      Ground
  2   PH0      Phase 0 state control
  3   GND      Ground
  4   PH1      Phase 1 state control
  5   GND      Ground
  6   PH2      Phase 2 state control
  7   GND      Ground
  8   PH3      Phase 3 register write
  9   NC       No connection
 10   /WRREQ   Write data request
 11   +5 V     +5 V
 12   SEL      Head select
 13   +12 V    +12 V
 14   /ENBL*   Drive enable
 15   +12 V    +12 V
 16   RD       Read data
 17   +12 V    +12 V
 18   WR       Write data
 19   +12 V    +12 V
 20   NC       No connection

Floppy Port
This info comes from Macintosh Repair and Upgrade Secrets by Larry Pina, © 1990, page 193-194.
If you intend to use this information, I strongly suggest that you read this book! There's some real gotchas. Keep in mind, for instance, that Macs have not had an external floppy port in a decade, and the socket header information dates back to when floppy disk drives were 400K or 800K! This info is even riskier than the rest of this page!

external DD  function 
DB-19 M      ---------------
 1           ground
 2           ground
 3           ground
 4           ground
 5           -12.00 V
 6           +5.00 V
 7           +12.00 V
 8           +12.00 V
 9           not connected 
10           speed (+5V motor speed control)
11           line CA0 (PH0 Register select CA0)
12           line CA1 (PH1 Register select CA1)
13           line CA2 (PH2 Register select CA2)
14           write strobe (PH3 Register write strobe LSTRB)
15           write request 
16           line SEL (SEL Register select line SEL)
17           external enable (Drive enable)
18           read data 
19           write data

internal                      | external 
disk drive                    | disk drive 
20-pin         function       | 20-pin         function 
socket header  ---------------| socket header  ---------------
 1             ground            1             ground
 2             line CA0          2             line CA0
 3             ground            3             ground
 4             line CA1          4             line CA1
 5             ground            5             ground
 6             line CA2          6             line CA2
 7             ground            7             ground
 8             write strobe      8             write strobe
 9             -12.00 V          9             not connected 
10             write request    10             write request 
11             +5.00 V          11             +5.00 V 
12             line SEL         12             line SEL 
13             +12.00 V         13             +12.00 V 
14             internal enable  14             external enable 
15             +12.00 V         15             +12.00 V 
16             read data        16             read data 
17             +12.00 V         17             not connected 
18             write data       18             write data 
19             +12.00 V         19             not connected 
20             speed            20             speed

30 pin Fast Page Mode SIMM 256kx8 256kx9 1Mx8 1Mx9 4Mx8 4Mx9

pin     assignment|pin  assignment|pin  assignment|pin  assignment 
1       Vcc       |9       Gnd    |17      A8     |25      DQ7 
2       -CAS      |10      DQ2    |18      A9     |26      QP 
3       DQ0       |11      A4     |19      A10    |27      -RAS 
4       A0        |12      A5     |20      DQ5    |28      -CASP 
5       A1        |13      DQ3    |21      -WE    |29      DP 
6       DQ1       |14      A6     |22      Gnd    |30      Vcc 
7       A2        |15      A7     |23      DQ6 
8       A3        |16      DQ4    |24      N/C

Notes:
QP, CASP and DP are N/C on all x8 bit modules
a9 is a N/C on 256k modules
a10 is a N/C on 256k and 1M modules

72 pin Fast Page Mode SIMM 256k/512k/1M/2M/4M/8M x 32/36 bit

pin     assignment|pin  assignment|pin  assignment|pin  assignment 
1       Gnd       |19      A10    |37      MP1    |55      DQ11 
2       DQ0       |20      DQ4    |38      MP3    |56      DQ27 
3       DQ16      |21      DQ20   |39      Gnd    |57      DQ12 
4       DQ1       |22      DQ5    |40      -CAS0  |58      DQ28 
5       DQ17      |23      DQ21   |41      -CAS2  |59      Vcc 
6       DQ2       |24      DQ6    |42      -CAS3  |60      DQ29 
7       DQ18      |25      DQ22   |43      -CAS1  |61      DQ13 
8       DQ3       |26      DQ7    |44      -RAS0  |62      DQ30 
9       DQ19      |27      DQ23   |45      -RAS1  |63      DQ14 
10      Vcc       |28      A7     |46      N/C    |64      DQ31 
11      N/C       |29      N/C    |47      -WE    |65      DQ15 
12      A0        |30      Vcc    |48      N/C    |66      N/C 
13      A1        |31      A8     |49      DQ8    |67      PD1 
14      A2        |32      A9     |50      DQ24   |68      PD2 
15      A3        |33      -RAS3  |51      DQ9    |69      PD3 
16      A4        |34      -RAS2  |52      DQ25   |70      PD4 
17      A5        |35      MP2    |53      DQ10   |71      N/C 
18      A6        |36      MP0    |54      DQ26   |72      Gnd

Notes:
MP0,MP1,MP2,MP3 are N/C on all x32 bit modules
a9 is a N/C on 256k and 512k modules
a10 is a N/C on 256k, 512k, 1M and 4M modules
RAS1/RAS3 are N/C on 256k, 1M and 4M modules

PCI Cards Universal/3.3V/5V and 32/64 bit

pin assignment |pin assignment |pin assignment |pin assignment 
B1  -12V       |A1   TRST#     |B48  AD[10]    |A48  Ground 
B2  TCK        |A2  +12V       |B49 Ground     |A49 AD[09] 
B3  Ground     |A3  TMS        |B50 (KEYWAY2)  |A50 (KEYWAY2) 
B4  TDO        |A4  TDI        |B51 (KEYWAY2)  |A51 (KEYWAY2) 
B5  +5V        |A5  +5V        |B52 AD[08]     |A52 C/BE[0]# 
B6  +5V        |A6  INTA#      |B53 AD[07]     |A53 +3.3V 
B7  INTB#      |A7  INTC#      |B54 +3.3V      |A54 AD[06] 
B8  INTD#      |A8  +5V        |B55 AD[05]     |A55 AD[04] 
B9  PRSNT1#    |A9  reserved   |B56 AD[03]     |A56 Ground 
B10 reserved   |A10 +Vi/o      |B57 Ground     |A57 AD[02] 
B11 PRSNT2#    |A11 reserved   |B58 AD[01]     |A58 AD[00] 
B12 (KEYWAY1)  |A12 (KEYWAY1)  |B59 Vi/o       |A59 +Vi/o 
B13 (KEYWAY1)  |A13 (KEYWAY1)  |B60 ACK64#     |A60 REQ64# 
B14 reserved   |A14 reserved   |B61 +5V        |A61 +5V 
B15 Ground     |A15 RST#       |B62 +5V        |A62 +5V 
B16 CLK        |A16 Vi/o       |B63 reserved   |A63 Ground 
B17 Ground     |A17 VNT#       |B64 Ground     |A64 C/BE[7]# 
B18 REQ#       |A18 Ground     |B65 C/BE[6]#   |A65 C/BE[5]# 
B19 +Vi/o      |A19 reserved   |B66 C/BE[4]#   |A66 +Vi/o 
B20 AD[31]     |A20 AD[30]     |B67 Ground     |A67 PAR64 
B21 AD[29]     |A21 +3.3V      |B68 AD[63]     |A68 AD[62] 
B22 Ground     |A22 AD[28]     |B69 AD[61]     |A69 Ground 
B23 AD[27]     |A23 AD[26]     |B70 +Vi/o      |A70 AD[60] 
B24 AD[25]     |A24 Ground     |B71 AD[59]     |A71 AD[58] 
B25 +3.3V      |A25 AD[24]     |B72 AD[57]     |A72 Ground 
B26 C/BE[3]#   |A26 IDSEL      |B73 Ground     |A73 AD[56] 
B27 AD[23]     |A27 +3.3V      |B74 AD[55]     |A74 AD[54] 
B28 Ground     |A28 AD[22]     |B75 AD[53]     |A75 +Vi/o 
B29 AD[21]     |A29 AD[20]     |B76 Ground     |A76 AD[52] 
B30 AD[19]     |A30 Ground     |B77 AD[51]     |A77 AD[50] 
B31 +3.3V      |A31 AD[18]     |B78 AD[49]     |A78 Ground 
B32 AD[17]     |A32 AD[16]     |B79 +Vi/o      |A79 AD[48] 
B33 C/BE[2]#   |A33 +3.3V      |B80 AD[47]     |A80 AD[46] 
B34 Ground     |A34 FRAME#     |B81 AD{45]     |A81 Ground 
B35 IRDY#      |A35 Ground     |B82 Ground     |A82 AD[44] 
B36 +3.3V      |A36 TRDY#      |B83 AD[43]     |A83 AD[42] 
B37 DEVSEL#    |A37 Ground     |B84 AD[41]     |A84 +Vi/o 
B38 Ground     |A38 STOP#      |B85 Ground     |A85 AD[40] 
B39 LOCK#      |A39 +3.3V      |B86 AD[39]     |A86 AD[38] 
B40 PERR#      |A40 SDONE      |B87 AD[37]     |A87 Ground 
B41 +3.3V      |A41 SBO#       |B88 +Vi/o      |A88 AD[36] 
B42 SERR#      |A42 Ground     |B89 AD[35]     |A89 AD[34] 
B43 +3.3V      |A43 PAR        |B90 AD[33]     |A90 Ground 
B44 C/BE[1]#   |A44 AD[15]     |B91 Ground     |A91 AD[32] 
B45 AD[14]     |A45 +3.3V      |B92 reserved   |A92 reserved 
B46 Ground     |A46 AD[13]     |B93 reserved   |A93 Ground 
B47 AD[12]     |A47 AD11]      |B94 Ground     |A94 reserved

Notes:
Pins 63-94 exist on 64 bit PCI implementation only
KEYWAY1 exists on Universal and 3.3V boards, they are Ground on 5V boards
KEYWAY2 exists on Universal and 5V boards, they are Ground on 3.3V boards
+Vi/o is 3.3V on 3.3V boards, 5V on 5V boards, and define signal rails on the Universal board.

HP-48 Serial Connector

HP48 
1  SHIELD 
2  TX 
3  RX 
4  Signal GND

HP48 to   HP48      Mac             PC-9    PC-25   Mac 
1,SHIELD  1,SHIELD  SHIELD,1,2,6,7  SHIELD  SHIELD  SHIELD 
2         3         5               2       3       5 
3         2         3               3       2       3 
4         4         4,8             5       7       4

Notes:
For convenience, I have added the HP-48 to: HP-48 4 pin, to Mac Mini DIN 8, to PC DB-9, and to PC DB-25 connections in one table. The first Mac column is based on a continuity test of my cable that works. The last Mac column is based on a newsgroup posting from 1993.
The HP-48 has 2 mm spacing between pins, not the much easier to find 0.1 inch spacing. Some hard drives, floppy drives, CD-ROM audio, and serial mouse innards use a 2 mm socket, but don't be fooled by ever-so-close 0.1 in. See the friendly HP-48 FAQ for more commentary.

Sun4 keyboard
The Sun Type 4 keyboard (mainly used on the Sun4) has a 8 pin Mini DIN Female connector. Sun has all of their documentation on the web and searchable.

1  GND              5  TxDA (Keyboard) 
2  GND              6  RxDA (Keyboard) 
3  Vcc              7  TxDB (Mouse) 
4  RxDB (Mouse)     8  Vcc

Sun SPARCstation 20 A/B serial port

 1  unused     11  B-DTR       21  A-DTR
 2  A-TxD      12  B-DCD       22  unused
 3  A-RxD      13  B-CTS       23  unused
 4  A-RTS      14  B-TxD       24  A-TxC out
 5  A-CTS      15  A-TxC in    25  B-TxC out (transmit clock out)
 6  A-DSR      16  B-RxD
 7  A&B-GND    17  A-RxC
 8  A-DCD      18  B-TxC in (transmit clock in)
 9  unused     19  B-RTS
10  unused     20  A-DTR

To use serial A (ttya) with a PC-style 9-pin serial port, use the following chart. Double-check the Mac column against the soon-to-be-added Mac-PC serial converter. The Category 5 type wiring color order corresponds to the PC pinouts numbering.

Mac  PC  SunA  sense  Cat5
nc   1    8    DCD    blue
8    2    3    RX     white/blue
6    3    2    TX     orange
2    4    20   DTR    white/orange
4    5    7    GND    green
nc   6    6    DSR    white/green
nc   7    4    RTS    brown
1    8    5    CTS    white/brown
nc   9    nc   (RI)   nc

Sun ShoeBox SCSI Connector

  1  -REQ        48    19+20,21+22,23+24
  2  -MSG        42    25 not used (26 is terminator power)
  3  -I/O        50    27+28,29+30,33+34
  4  -RST        40
  5  -ACK        38
  6  -BSY        36
  7  GROUND      1+3+5
  8  DATA-0      2
  9  GROUND      7+9+11
 10  DATA-3      8
 11  DATA-5      12
 12  DATA-6      14
 13  DATA-7      16
 14  GROUND      45+47+49
 15  -C/D        46
 16  GROUND      39+41+43
 17  -ATN        32
 18  GROUND      31+35+37
 19  -SEL        44
 20  PARITY      18
 21  DATA-1      4
 22  DATA-2      6
 23  DATA-4      10
 24  GROUND      13+15+17
 25  TERM-POWER  26

Notes:
All active even numbered pins (2n) have a corresponding ground wire (2n-1).
If you're paranoid, you might want to avoid the use of pin 25 on the DB-25 and pin 26 of the DD-50. This is because external SCSI disk boxes have this pin grounded, instead of using it to supply +5 volts to the termination resistors.

Serial Port DB-9 Male and DB-25 Male

9-pin   25-pin  assignment 
1       8       DCD    Data Carrier Detect 
2       3       RX     Receive Data 
3       2       TX     Transmit Data 
4       20      DTR    Data Terminal Ready 
5       7       GND    Signal Ground 
6       6       DSR    Data Set Ready 
7       4       RTS    Request To Send 
8       5       CTS    Clear To Send 
9       22      RI     Ring Indicator

Serial Port loopback

Connected Pins
RX & TX
RTS & CTS
DCD & DTR & DSR & RI

Null Modem

Connector 1 to  Connector 2 
DTR             DSR/DCD 
DSR/DCD         DTR 
RTS             CTS 
CTS             RTS 
TXD             RXD 
RXD             TXD 
GND             GND

Parallel Port DB-25 Female

pin     assignment      pin     assignment 
1       -Strobe         2       Data 0 
3       Data 1          4       Data 2 
5       Data 3          6       Data 4 
7       Data 5          8       Data 6 
9       Data 7          10      -Ack 
11      Busy            12      Paper Empty 
13      Select          14      -Auto Feed 
15      -Error          16      -Init 
17      -Slct in        18      GND 
19      GND             20      GND 
21      GND             22      GND 
23      GND             24      GND 
25      GND

Parallel Port Centronics-36

1       -Strobe         2       Data 0 
3       Data 1          4       Data 2 
5       Data 3          6       Data 4 
7       Data 5          8       Data 6 
9       Data 7          10      -Ack 
11      Busy            12      Paper Empty 
13      Select          14      -Auto Feed 
15      {OSCXT}         16      Signal GND 
17      Frame GND       18      +5v 
19      GND             20      GND 
21      GND             22      GND 
23      GND             24      GND 
25      GND             26      GND 
27      GND             28      GND 
29      GND             30      GND 
31      -Prime          32      -Error 
33      Signal GND      34      N/C 
35      N/C             36      N/C

Parallel Port loopback DB-25 Male

Connected Pins
2 & 15
3 & 13
4 & 12
5 & 10
6 & 11

Bidirectional (Laplink) Parallel Cable DB-25 Male to DB-25 Male

Connector 1 to  Connector 2 
2               15 
3               13 
4               12 
5               10 
6               11 
10              5 
11              6 
12              4 
13              3 
15              2 
16              16 
17              17 
25              25

Game Port DB-15 Female

pin     assignment      pin     assignment 
1       +5V DC          2       Button 4 (A_PB1) 
3       Position 0(A_X) 4       GND 
5       GND             6       Position 1 (A_Y) 
7       Button 5(A_PB2) 8       +5V DC 
9       +5V DC          10      Button 6 (B_PB1) 
11      Position 2(B_X) 12      GND 
13      Position 3(B_Y) 14      Button 7 (B_PB2) 
15      +5V DC

MIDI 5 pin DIN

   MIDI In                 MIDI Out 
pin     assignment      pin     assignment 
1       N/C             1       N/C 
2       N/C             2       GND 
3       N/C             3       N/C 
4       Current Src     4       Current Sink 
5       Current Sink    5       Current Src

VGA DB-15 Female DB-9 Female

15-pin  9-pin   assignment 
1       1       Red 
2       2       Green 
3       3       Blue 
4       -       Monitor ID bit 2 
5       -       N/C 
6       6       GND (red return) 
7       7       GND (green return) 
8       8       GND (blue return) 
9       -       N/C 
10      -       GND 
11      -       Monitor ID bit 0 
12      -       Minitor ID bit 1 
13      4       Horizontal Sync 
14      5       Vertical Sync 
15      -       N/C

Monitor ID bit 0: reserved
Monitor ID bit 1: GND = mono, OPEN = color
Monochrome monitors use the green signal

CGA DB-9 Female

pin   assignment 
1     GND 
2     GND 
3     Red 
4     Green 
5     Blue 
6     Intensity 
7     (reserved) 
8     Horizontal Sync 
9     Vertical Sync

EGA DB-9 Female

pin   assignment 
1     GND 
2     Secondary Red 
3     Primary Red 
4     Primary Green 
5     Primary Blue 
6     Secondary Green / Intensity 
7     Secondary Blue / Mono Video 
8     Horizontal Drive 
9     Vertical Drive

Power Connector Male

pin     assignment 
1       +12V 
2       +12V return  GROUND 
3       +5V return   GROUND 
4       +5V

Speaker Connector

pin     assignment 
1       -Speaker 
2       [key] 
3       GND 
4       +Speaker +5V

AT Keyboard Connector 5 pin DIN

pin     assignment 
1       CLK/CTS (open-collector) 
2       RxD/TxD/RTS (open-collector) 
3       N/C 
4       GND 
5       +5V

XT Keyboard Connector 5 pin DIN

pin     assignment 
1       CLK/CTS (open-collector) 
2       Keyboard Data 
3       Reset 
4       GND 
5       +5V

PS2 Keyboard/Mouse Connector 6 pin Mini DIN

pin     assignment 
1       Data 
2       N/C 
3       GND 
4       Vcc 
5       CLK 
6       N/C

PS2 6 pin Mini DIN to AT 5 pin DIN Keyboard Adapter

pin-PS2(F)  pin-AT(M) 
1           2 
2           N/C 
3           4 
4           5 
5           1 
6           N/C

Back to Joni's

Created: June 16, 1998
Last Revised: January 28, 2000

This URL: http://www.bme.unc.edu/~hope/linx/mac/pinouts.html
Copyright 1998 (what parts aren't FAQ) by Joni Julian

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