This information compiled and provided by
Dick Perron dperr@randomc.com
Standard PC Cabling Pin-out Diagrams
Standard motherboard power connectors
ATX motherboard power connector
CGA/EGA/VGA Video connectors
DB13W3 Mono and Color video connectors
AT and PS/2 keyboard connectors
PS2/Serial mouse adaptor
PS2/Serial mouse connectors
IBM and EVEREX serial ribbon cable pinout
Serial I/O connectors
Game Port Connector
Reset/keylock/battery/speaker/HDD/turbo MB connectors
Parallel I/O connectors
Serial Loopback Plug Wiring
Parallel Loopback Plug Wiring
Win95/98 Direct Cable Connection (Serial and Parallel)
Null modem cable PC to PC
Null modem cable PC to serial device
Parallel Centronics cable
MIDI In and Out connectors
IR module connector
USB Canle Connector
10baseT/100baseT crossover cable
100baseT4 crossover cable
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CENTRONICS/DB STYLE CONNECTOR PIN NUMBERING
Rule of thumb for pin numbering for standard and mini Centronics/DB style connectors is:
Male Connectors
Pin #1 is the first pin, top row, LEFT side when looking at the connector.
Female Connectors
Pin #1 is the first pin, top row, RIGHT side when looking at the connector.
DIN/MINI-DIN CONNECTORS
DIN and Mini-Din connectors have an alternating pin numbering scheme. See
diagrams in this document for correct pin orientation.
******************************************************************************
STANDARD PC MOTHERBOARD CONNECTORS
Main Board (System PCB) Standard DC Power Connector(s)
O Y
r e B B B B W
a l B l l l l h
n R l l a a a a i R R R
g e o u c c c c t e e e
e d w e k k k k e d d d
___________ ____________
| | | |
| P8 | | P9 |
| | | |
----------- -----------
Wire Color Assignment
Black ------------------------------- Ground
Orange -------------------------- Power Good (+5V DC)
Red ---------------------------------- +5 VDC
White --------------------------------- -5 VDC
Yellow ------------------------------- +12 VDC
Blue -------------------------------- -12 VDC
Note!! When installing the P8/P9 connector be sure that the four
black wires are adjacent to each other in the center of the connector.
The Red and Orange wires are on the outside edge of the connector.
ATX 20 pin power connector
Pin# Pin#
-----------------------
| 3.3V 11 1* 3.3V |
| -12V 12 2 3.3V |
| COM 13*(Gnd) 3 COM |
| PS-ON 14* 4 +5V |
| COM 15 5 COM |
| COM 16 6 +5V |
| COM 17 7 COM |
| -5V 18 8 PW-OK|
| +5V 19 9 5VSB |
| +5V 20 10 +12V |
--------------------------
* NOTE!! On ATX supplies the power supply on/off functions are controlled thru the motherboard connector.
See pins 1, 13 and 14 for 3.3V, GND and power on signal.
Peripheral DC Power Connector
Y
B B e
l l l
R a a l
e c c o
d k k w
Wire Color Assignment
Red ------------------------------- +5 VDC
Black ------------------------------ Ground
Yellow ----------------------------- +12 VDC
IBM AT 101 KEY (ENHANCED) KEYBOARD 5 PIN DIN CONNECTOR
Male End PIN SIGNAL Female End
1 ---------------------------------- KBDCLK (clock)
1 3 2 ---------------------------------- KBDAT (data) 3 1
4 5 3 ---------------------------------- KBRST (reset,not used) 5 4
2 4 ---------------------------------- GND 2
5 ---------------------------------- VCC (+5V)
IBM PS/2 KEYBOARD 6 PIN MINI-DIN CONNECTOR
Male End PIN SIGNAL
5 H 6 1 -------------------------------- KBDAT (data)
3 4 2 -------------------------------- not used
1 2 3 -------------------------------- GND
4 -------------------------------- VCC (+5v)
5 -------------------------------- KBCLK (clock)
6 -------------------------------- not used
IBM PS/2 MOUSE 6 PIN MINI-DIN CONNECTOR
PIN SIGNAL
6 H 5 1 ------------------------------- MOUSEDATA: 110
4 3 2 ------------------------------- not used
2 1 3 ------------------------------- GND
4 ------------------------------- +5V
Female end 5 ------------------------------- MOUSECLK: 110
6 ------------------------------- not used
PS/2 MOUSE ADAPTOR CABLE TO MOTHERBOARD 10 PIN DIL CONN
Mouse port DIL Conn
1 ------------------------------- 1 Data
2 ------------------------------- 2 N/C
3 ------------------------------- 3 Gnd
4 ------------------------------- 4 VCC +5V
5 ------------------------------- 5 Clk
NOTE!! This pinout is from a Biostar MB with PS2 mouse option.
This PS2 to DIL connector cable IS NOT STANDARD
across all MB mfg's. There are some 4 pin , 5 pin and
10 pin DIL connectors on various MB's.
SERIAL MOTHERBOARD CABLE 10 PIN DIL TO DB-9
(IBM WIRING SCHEME)
This is the ribbon cable from the MB serial
connector to the DB-9/DB-25 COM connector
DIL DB-9 DB-25
1 -------------- 1 DCD __________ 8
6 -------------- 2 RX ___________ 3
2 -------------- 3 TX ___________ 2
7 -------------- 4 DTR __________ 20
3 -------------- 5 GND __________ 7
8 -------------- 6 DSR __________ 6
4 -------------- 7 RTS __________ 4
9 -------------- 8 CTS __________ 5
5 -------------- 9 RI ___________ 22
10 ------------- 10 N/C OR KEY
SERIAL MOTHERBOARD CABLE 10 PIN DIL TO DB-9
(EVEREX WIRING SCHEME)
This is the ribbon cable from the MB serial
connector to the DB-9/DB-25 COM connector
DIL DB-9 DB-25
1 -------------- 1 DCD __________ 8
2 -------------- 2 RX __________ 3
3 -------------- 3 TX __________ 2
4 -------------- 4 DTR __________ 20
5 -------------- 5 GND __________ 7
6 -------------- 6 DSR __________ 6
7 -------------- 7 RTS __________ 4
8 -------------- 8 CTS __________ 5
9 -------------- 9 RI __________ 22
10 ------------- 10 N/C OR KEY
MICROSOFT SERIAL MOUSE DB-9 CONNECTOR
PIN SIGNAL
1 -------------------------------- MOUSEDATA
5 -------------------------------- Gnd
8 -------------------------------- +5V
9 -------------------------------- MOUSECLOCK
PS2/SERIAL MOUSE ADAPTOR CABLE
MINI DIN CONN DB-9 SERIAL CONN
1 ---------------------------------- 1
3 ---------------------------------- 5
4 ---------------------------------- 8
5 ---------------------------------- 9
GAME PORT DB-15 FEMALE
PIN SIGNAL
1 -------------------------------- +5V DC
2 -------------------------------- Button 4 (A_PB1)
3 -------------------------------- Pos'n 0 (A_X)
4 -------------------------------- GND
5 -------------------------------- GND
6 -------------------------------- Pos'n 1 (A_Y)
7 -------------------------------- Button 5 (A_PB2)
8 -------------------------------- +5V DC
9 -------------------------------- +5V DC
10 -------------------------------- Button 6 (B_PB1)
11 -------------------------------- Pos'n 2 (B_X)
12 -------------------------------- GND
13 -------------------------------- Pos'n 3 (B_Y)
14 -------------------------------- Button 7 (B_PB2)
15 -------------------------------- +5V DC
KEYLOCK AND POWER LED CONNECTOR
PIN SIGNAL
1 -------------------------------- +5 VDC
2 -------------------------------- not used (key)
3 and 5 -------------------------- GND
4 -------------------------------- KEYBD DIS (key lock)
EXTERNAL BATTERY CONNECTOR (6 VDC)
PIN SIGNAL
1 -------------------------------- +6 VDC
2 -------------------------------- not used (key)
3 -------------------------------- GND
4 -------------------------------- GND
SPEAKER CONNECTOR
PIN SIGNAL
1 -------------------------------- SPEAKER
2 -------------------------------- not used (key)
3 -------------------------------- GND
4 -------------------------------- +5 VDC
TURBO LED CONNECTOR
PIN SIGNAL
1 -------------------------------- +TURBO (+5 VDC)
2 -------------------------------- GND
DISK ACCESS LED CONNECTOR
PIN SIGNAL
1 -------------------------------- +DISK (+5 VDC)
2 -------------------------------- -DISK
3 -------------------------------- -DISK
4 -------------------------------- +DISK (+5VDC)
ENHANCED GRAPHICS ADAPTOR (EGA) VIDEO CONNECTOR DB-9
DB-9 PIN female SIGNAL
DB-9 MALE CONN 1 -------------------------------- GND DB-9 FEMALE CONN
1 5 2 -------------------------------- SECONDARY RED 5 1
o o o o o 3 -------------------------------- RED o o o o o
o o o o 4 -------------------------------- GREEN o o o o
6 9 5 -------------------------------- BLUE 9 6
6 ---------------------- SECONDARY GREEN/INTENSITY
7 ---------------------- SECONDARY BLUE/MONO VIDEO
8 -------------------------------- HORIZ RETRACE
9 -------------------------------- VERT RETRACE
VIDEO GRAPHICS ARRAY (VGA) HDD-15 CONNECTOR
HDD-15 PIN female SIGNAL
HDD 15 MALE CONN 1 -------------------------------- RED HDD 15 FEMALE CONN
1 5 2 -------------------------------- GREEN 5 1
o o o o o 3 -------------------------------- BLUE o o o o o
6 o o o o o 10 4 ------------------------- MONITOR ID BIT 2 10 o o o o o 6
o o o o o 5 -------------------------------- DIGITAL GND o o o o o
11 15 6 --------------------------- RED ANALOG GND 15 11
7 --------------------------- GREEN ANALOG GND
8 --------------------------- BLUE ANALOG GND
9 ------------------------------ not used
10 -----------------------------SYNC RETURN (GND)
11 ------------------------ MONITOR ID BIT 0 (not usually used)
12 ------------------------ MONITOR ID BIT 1 (not usually used)
13 ----------------------------- HORIZ SYNC
14 ----------------------------- VERT SYNC
15 ----------------------------- not used
WORKSTATION VIDEO GRAPHICS DB13W3 CONNECTOR
DB13W3 female COLOR SIGNAL
DB13W3 MALE CONN 1 -------------------------------- N/C DB13W3 FEMALE CONN
1 5 2 -------------------------------- N/C 5 1
o o o o o 3 -------------------------------- SENSE2 o o o o o
@ o o o o o @ @ 4 ------------------------- -------SRTN @ @ o o o o o @
A1 6 10 A2 A3 5 -------------------------------- CSYNC A3 A2 10 6 A1
6 -------------------------------- N/C
7 -------------------------------- N/C
8 -------------------------------- SENSE1
9 -------------------------------- SENS0
10 ------------------------------- CRTN
A1 ------------------------------- RED
A2 ------------------------------- GREEN
A3 ------------------------------- BLUE
DB13W3 female GREYSCALE (MONO) SIGNAL
1 -------------------------------- N/C
2 -------------------------------- N/C
3 -------------------------------- SENSE2
4 -------------------------------- SRTN
5 -------------------------------- CSYNC
6 -------------------------------- N/C
7 -------------------------------- N/C
8 -------------------------------- SENSE1
9 -------------------------------- SENS0
10 ------------------------------- CRTN
A1 ------------------------------- N/C
A2 ------------------------------- GREEN
A3 ------------------------------- N/C
NOTE!! Most workstation monitors using DB13W3 connectors are FIXED FREQUENCY or are
sync on green monitors and cannot be used as standard VGA monitors on a PC
without a special GRFX card to match the horiz/vert frequency requirements
of the monitor.
COLOR GRAPHICS ADAPTER (CGA) VIDEO CONNECTOR DB-9
DB-9 PIN Female SIGNAL
1 --------------------------------- GND
2 --------------------------------- GND
3 --------------------------------- RED
4 --------------------------------- GREEN
5 --------------------------------- BLUE
6 ------------------------------- INTENSITY
7 -------------------------------- not used
8 ------------------------------ HORIZ SYNC
9 ------------------------------ VERT SYNC
MONOCHROME ADAPTOR DB-9
DB-9 PIN Female SIGNAL
1 --------------------------------- GND
2 --------------------------------- GND
3 ------------------------------- not used
4 ------------------------------- not used
5 ------------------------------- not used
6 ----------------------------- +INTENSITY
7 ------------------------------- +VIDEO
8 ------------------------------ +HORIZ SYNC
9 ------------------------------- -VERT SYNC
PARALLEL PRINTER CONNECTOR DB-25
DB-25 PIN (Female) SIGNAL
DB-25 MALE CONN 1 ------------------------------- > STROBE * DB-25 FEMALE CONN
1 13 2 ------------------------------- > DATA 0 13 1
ooooooooooooo 3 ------------------------------- > DATA 1 ooooooooooooo
ooooooooooo 4 ------------------------------- > DATA 2 ooooooooooo
14 25 5 ------------------------------- > DATA 3 25 14
6 ------------------------------- > DATA 4
7 ------------------------------- > DATA 5
8 ------------------------------- > DATA 6
9 ------------------------------- > DATA 7
10< ------------------------------ ACK *
11< ------------------------------ BUSY
12< ------------------------------ PAPER END
13 ------------------------------ SLCT (select)
14 ------------------------------ >AUTOFEED *
15< ------------------------------ ERROR *
16 --------------------------->INITIALIZE PRINTER *
17 ------------------------------- SLCTIN (select in)
18 thru 25 ----------------------- GND
Note!! * denotes an active low signal.
DB-25 MALE PARALLEL LOOPBACK CONNECTOR WIRING
1 to 13 Strobe to select
2 to 15 Data o to ERROR
10 to 16 ACK to INIT
11 to 17 BUSY to SLCTIN
12 to 14 PAPER END to AUTOFEED
SERIAL I/O PIN OUTS
RS-232 SERIAL (COM) PC PORT CONNECTOR DB-9
DB-9 PIN (Male) FUNCTION ABBREVIATION
1 --------------------------- Data Carrier Detect CD or DCD
2 ------------------------------ Receive Data RD or RX
3 ---------------------------- Transmitted Data TX or TD
4 ---------------------------- Data Terminal Ready DTR
5 ------------------------------ Signal Ground GND
6 ------------------------------ Data Set Ready DSR
7 ------------------------------ Request To Send RTS
8 ------------------------------ Clear To Send CTS
9 ------------------------------ Ring Indicator RI
Transmitted and receive data are referenced from the data device and
not the modem.
RS-232 SERIAL (COM) PC PORT CONNECTOR DB-25
DB-25 PIN (Male) FUNCTION ABBREVIATION
1 ---------------------------- Chassis/Frame Ground GND
2 ------------------------------ Transmitted Data TX or TD
3 -------------------------------- Receive Data RX or RD
4 ------------------------------ Request To Send RTS
5 ------------------------------- Clear To Send CTS
6 ------------------------------- Data Set Ready DSR
7 ------------------------------- Signal Ground GND
8 ---------------------------- Data Carrier Detect DCD or CD
9 ------------------------- Transmit + (Current loop) TD+
11 ------------------------ Transmit - (Current Loop) TD-
18 ------------------------- Receive + (Current Loop) RD+
20 --------------------------- Data Terminal Ready DTR
22 ----------------------------- Ring Indicator RI
25 ------------------------- Receive - (Current Loop) RD-
NOTE!! Current loop technology was supported in the PC and XT interfaces.
Current loop was discontinued when the AT interface was introduced.
Transmitted and receive data are referenced from the data
device and not the modem.
DB-25 FEMALE SERIAL LOOPBACK PLUG WIRING
2 to 3 Xmit to Rec data
4 to 5 to 22 RTS to CTS to RI
6 to 8 to 20 DSR to CD to DTR
DB-9 FEMALE SERIAL LOOPBACK PLUG WIRING
2 to 3 Xmit to Rec data
7 to 8 to 9 RTS to CTS to RI
6 to 1 to 4 DSR to CD to DTR
SERIAL PORT LOOPBACK DIAGNOSTIC TESTING RULES
When the diagnostic asserts RTS (output) it then tests for the presence
of CTS and Ring Indicator (input). If CTS and RI are detected the RTS driver and
CTS/RI receivers are considered operational. When DTR is asserted (output) the
diagnostic tests for the presence of CD and DSR (input). If CD/DSR are detected
the DTR driver and CD/DSR receivers are considered operational. Data is Xmitted
and received on the data lines and the data is compared in the diagnostic buffer.
If any status's are not detected an error message is displayed.
RS-232 SERIAL DB-9 to RS-232 DB-25 ADAPTOR
DB-9 PIN (Female) DB-25 PIN (Male)
1 ------------------------------------- 8 DCD
2 ------------------------------------- 3 TXD
3 ------------------------------------- 2 RXD
4 ------------------------------------- 20 DTR
5 ------------------------------------- 7 GND
6 ------------------------------------- 6 DSR
7 ------------------------------------- 4 RTS
8 ------------------------------------- 5 CTS
9 ------------------------------------- 22 RI
Use this pin out to adapt between the two serial connector
types.
RS-232 SERIAL DB-25 to DB-25 NULL MODEM CABLE
DB-25 PIN (Female) PC DB-25 PIN (Female) PC
2 ------------------------------------- 3
3 ------------------------------------- 2
7 ------------------------------------- 7
4 ------------------------------------- 5
5 ------------------------------------- 4
6 ------------------------------------- 20
20 ------------------------------------ 6
Note!! All other pins are unused. Use this cable pinout for direct
connection between two IBM compatible computers. (LAPLINK)
RS-232 SERIAL DB-25 to SERIAL PRINTER NULL MODEM CABLE
DB-9 Female PC DB-25 PIN Female PC DB-25 PIN Male printer
2 < RD --------- 3 <------------------------------------- 2 Transmitted data
3 > TD --------->2 -------------------------------------> 3 Receive data
5 < GND -------- 7 <------------------------------------> 7 Ground
8 < CTS -------- 5 ------------------------------------ 6 to 8 to 20
1 to 4 to 6 6 to 8 to 20 4 to 5
DTR/DSR/DCD DTR/DSR/DCD RTS to CTS
Note!! Use this cable pinout for direct connection between a PC
serial port and a serial printer. The 1/4/6 and 6/8/20
loopbacks are to enable the interface as if a modem was attached.
Win95/98 Direct Cable Connection Interlink Cable (Serial port)
DB-9---DB-25 (Female) DB-25---DB-9 (Female)
5 7 <------------------------------> 7 5 Gnd-Gnd
3 2 <------------------------------> 3 2 Xmit-Recv data
7 4 <------------------------------> 5 8 RTS-CTS
1&6 6 <------------------------------> 20 4 DSR-DTR
2 3 <------------------------------> 2 3 Recv-Xmit data
8 5 <------------------------------> 4 7 CTS-RTS
4 20<------------------------------> 6 1&6 DTR-DSR
Win95/98 Direct Cable Connection Interlink Cable Parallel port (4 bit)
DB-25(Male) DB-25(Male)
2 <------------------------------> 15 N/A
3 <------------------------------> 13 N/A
4 <------------------------------> 12 N/A
5 <------------------------------> 10 N/A
6 <------------------------------> 11 N/A
15 <------------------------------> 2 N/A
13 <------------------------------> 3 N/A
12 <------------------------------> 4 N/A
10 <------------------------------> 5 N/A
11 <------------------------------> 6 N/A
25 <------------------------------> 25 Ground-Ground
ECP Direct Cable Connection (8 bit) Untested, For the experts only!
This pinout was listed for testing two parallel ports and is thought
to be correct for running two computers via ECP Direct Cable Connection.
DB-25 Male DB-25 Male
nStrobe 1 <---------------------------------> 10 nACK
Data 0 2 <---------------------------------> 2 Data 0
Data 1 3 <---------------------------------> 3 Data 1
Data 2 4 <---------------------------------> 4 Data 2
Data 3 5 <---------------------------------> 5 Data 3
Data 4 6 <---------------------------------> 6 Data 4
Data 5 7 <---------------------------------> 7 Data 5
Data 6 8 <---------------------------------> 8 Data 6
Data 7 9 <---------------------------------> 9 Data 7
nACK 10 <---------------------------------> 1 nStrobe
Busy 11 <---------------------------------> 14 nAutoFwd
PError 12 <---------------------------------> 16 nInit
Select 13 <---------------------------------> 13,17 Select, nSelectIn
nFault 14 <---------------------------------> 17 nSelectIn
nAutofwd 15 <---------------------------------> 11 Busy
nInit 16 <---------------------------------> 12 PError
nSelectIn 17 <---------------------------------> 15 nFault
Gnd 18-25 <------------------------------> 18-25 Gnd
STANDARD CENTRONICS PARALLEL CABLE DB-25 TO CENTRONICS 36
DB-25 PIN Male (PC) Centronics 36 Male
CENTRONICS 36 MALE 1 --------------------------------------> 1 Strobe * CENTRONICS 36 FEMALE
1 CONNECTOR 18 2 <-------------------------------------> 2 Data bit 0 + 18 CONNECTOR 1
\ ------------------ / 3 <-------------------------------------> 3 Data bit 1 + \ ------------------ /
\------------------/ 4 <-------------------------------------> 4 Data bit 2 + \------------------/
19 36 5 <-------------------------------------> 5 Data bit 3 + 36 19
6 <-------------------------------------> 6 Data bit 4+
7 <-------------------------------------> 7 Data bit 5 +
8 <-------------------------------------> 8 Data bit 6 +
9 <-------------------------------------> 9 Data bit 7 +
10 <------------------------------------- 10 Acknowledge *
11 <------------------------------------- 11 Busy +
12 <------------------------------------- 12 Paper out +
13 <------------------------------------- 13 Select (in) *
14 -------------------------------------> 14 Auto Feed *
15 <------------------------------------- 32 Error *
16 -------------------------------------> 31 Initialize printer *
17 -------------------------------------> 36 Select (out) *
18 thru 25 Gnd 16, 19 thru 30, 33 Ground
15, 17, 18, 34, 35 No connection
Note!! * denotes and active low signal. This pin out depicts the newer bi-directional parallel
port with input and output capabilities often used with external tape drives and
accessory devices. If pins 31 or 32 are grounded on a cable the printer will fail to
come ready when attached to the PC. This is common on low cost parallel printer cables.
MIDI 5 PIN DIN IN AND OUT CONNECTORS
MIDI In MIDI Out
pin Signal pin Signal
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
IR Module Connector
Pin Signal
1 ----------------------------- IRTX
2 ----------------------------- GND
3 ----------------------------- IRRX
4 ----------------------------- N/C
5 ----------------------------- Vcc
USB Cable Connector
Pin Signal
A1 ------------------------------ Vcc
A2 ------------------------------ Port0 data-
A3 ------------------------------ Port0 data+
A4 ------------------------------ Gnd
B1 ------------------------------ Vcc
B2 ------------------------------ Port1 data-
B3 ------------------------------ Port1 data+
B4 ------------------------------ Gnd
10baseT and 100baseTX crossover cable diagram
For direct connection from NIC to NIC with no hub
RJ45 Pin# RJ45 pin#
TD+ 1 <-----------------------------> 3 RD+
TD- 2 <-----------------------------> 6 RD-
RD+ 3 <-----------------------------> 1 TD+
RD- 6 <-----------------------------> 2 TD-
The receive data pair (the two wires designated RD) must be a twisted
pair, and the transmit data pair (designated TD) must be a twisted pair.
When using 10 Megabit (10baseT), category 3, 4 or 5 cable may be
used. When using 100 Megabit (100baseTX), the cable must be category 5.
100baseT4 crossover cable diagram
For direct connection from NIC to NIC with no hub
RJ45 pin# RJ45 pin#
TX_D1+ 1 <--------------------------> RX_D2+ 3
TX_D1- 2 <--------------------------> RX_D2- 6
RX_D2+ 3 <--------------------------> TX_D1+ 1
BI_D3+ 4 <--------------------------> BI_D4+ 7
BI_D3- 5 <--------------------------> BI_D4- 8
RX_D2- 6 <--------------------------> TX_D1- 2
BI_D4+ 7 <--------------------------> BI_D3+ 4
BI_D4- 8 <--------------------------> BI_D3- 5
The receive data pair (the two wires designated RX_D2) must be a
twisted pair, the transmit data pair (designated TX_D1) must be a twisted
pair, the first bi-directional pair (designated BI_D3) must be a twisted pair
and the second bi-directional pair (designated BI_D4) must be a twisted
pair. Category 3, 4 or 5 cable may be used.
Note: These are not IEEE supported configurations and as such, these pinouts
are only supported for test purposes. (they do work in practice)