Unless otherwise noted, credit for pinout images and information from Pinouts.ru - every connector type links back to corresponding Pinouts.ru page

RCA

BNC


Image credit to Thor Labs

Tip-Sleeve

Tip-Ring-Sleeve

Balanced Mono

Pin Description
1 In Phase/Hot
2 Out of Phase/Cold
3 Ground

Unbalanced Stereo

Pin Description
1 Signal (Left Channel)
2 Signal (Right Channel)
3 Ground

XLR

Balanced Audio

Pin Description
1 Ground
2 In Phase/Hot
3 Out of phase/Cold

AES/EBU

Pin Description
1 Ground
2 Data (Channel 1)
3 Data (Channel 2)

Mini-DIN 4-pin

S-Video

Pin Description
1 Ground (Y)
2 Ground (C)
3 Luminance (Y)
4 Chrominance (C)

Apple Desktop Bus

Pin Description
1 ADB bidirectional data
2 Power switch
3 Power +5V
4 Ground

DIN 5-pin

Unbalanced Audio

Pin Description
1 Signal Input (Left channel)
2 Ground
3 Signal Output (Left channel)
4 Signal Input (Right channel)
5 Signal Output (Right channel)

MIDI

Pin Description
1 Not connected
2 Shield (input)/Ground (output)
3 Not connected
4 Signal (source on input, sink on output)
5 Signal (sink on input, source on output)

Mini-DIN 6-pin

PS/2

Pin Description
1 Key data (keyboard), Button/Position data (mouse)
2 not connected
3 Ground
4 Power, +5V
5 Clock
6 not connected

DIN 7-pin

Image credit to captain18 at LiveJournal

eSATA

Pin Description
1 Ground
2 Transmit+ (data)
3 Transmit- (data)
4 Ground
5 Receive+ (data)
6 Receive- (data)
7 Ground

8-pin EIAJ

Image credit to Lab Guy's World

Pin Description
1 Audio out
2 Video out
3 Video in
4 Video in
5 Audio out
6 Video out
7 Audio in
8 Audio in

Mini-DIN 8-pin

Apple RS-422

Pin Description
1 Output Handshake
2 Input Handshake or External Clock
3 Transmit- (data)
4 Ground
5 Receive data- (data)
6 Transmit data+ (data)
7 General Purpose Input
8 Receive data- (data)

DE-9

RS-232

Pin Description
1 Carrier detect
2 Receive data
3 Transmit data
4 Data terminal ready
5 Ground
6 Data set ready
7 Request to send
8 Clear to send
9 Ring indicator

Sony 9-pin RS-422 VTR protocol

Pin Description
1 Frame ground
2 Transmit A
3 Receive B
4 Receive common
5 spare/ground
6 Transmit common
7 Transmit B
8 Receive A
9 Frame ground

Mini-VGA

Pin VGA input Video output
1 Ground Ground
2 Vertical Sync not used
3 Horizontal Sync not used
4 Red return Ground
5 Red video S-Video Chroma (C)
6 Green return Ground
7 Green video S-Video Luma (Y)
8 Power +5V Power +5V
9 Blue video Composite video
10 DDC data DDC data
11 DDC clock DDC clock
12 Ground
13 Cable detect Cable detect
14 Blue return Ground

DA-15

Joystick Connector

Pin Signal name Description
1 +5v Power
2 A Right Button Joystick/A Right Button
3 A / X-position Joystick/A X-Coordinate
4 Signal GND Ground
5 Signal GND Ground
6 A / Y-position Joystick/A Y-Coordinate
7 A Left Button Joystick/A Left Button
8 +5v Power
9 +5v Power
10 B Right Button Joystick/B Right Button
11 B / X-position Joystick/B X-Coordinate
12 MIDI Out MIDI Output
13 B / Y-position Joystick/B Y-Coordinate
14 B Left Button Joystick/B Left Button
15 MIDI In MIDI Input

DA-15 had highly varied pinouts depending on the specific peripheral in question. See pinouts.ru for more options.

DE-15

VGA

Pin Description
1 Red video
2 Green video
3 Blue video
4 reserved
5 Ground
6 Red ground
7 Green ground
8 Blue ground
9 Key (no pin)/Optional +5V power output
10 Sync ground
11 Monitor ID Bit 0 (optional)
12 I2C bidirectional data
13 Horizontal Sync
14 Vertical Sync
15 I2C data clock

USB

USB 2.0

Pin Type A/Type B Mini-A/Mini-B Micro-A/Micro-B
1 Power +5V Power +5V Power +5V
2 Data - Data - Data -
3 Data + Data + Data +
4 Ground Ground/Attached device indicator/not connected Ground/attached device indicator/ground
5 Ground Ground

USB 3.0

Pin Type A Type B Powered B Micro-B
1 Power +5V Power +5V Power +5V Power +5V
2 Data - (2.0 speed) Data - (2.0 speed) Data - (2.0 speed) Data - (2.0 speed)
3 Data + (2.0 speed) Data + (2.0 speed) Data + (2.0 speed) Data + (2.0 speed)
4 Ground (power) Ground (power) Ground (power) ID configuration line
5 RX- (Superspeed receiver) TX- TX- Ground
6 RX+ (Superspeed receiver) TX+ TX+ TX-
7 Ground (signal) Ground (signal) Ground (signal) TX+
8 TX- (Superspeed transmitter) RX- RX- Ground
9 TX+ (Superspeed transmitter) RX+ RX+ RX-
10 Power provided by device RX+
11 Ground for power provided by device

USB 3.1

Pin Type C
A1 Ground
A2 TX1+ (Superspeed transmitter)
A3 TX1- (Superspeed transmitter)
A4 Power
A5 CC1 (orientation configuration information)
A6 Data+ (2.0 speed)
A7 Data- (2.0 speed)
A8 Secondary bus 1
A9 Power
A10 RX2- (Superspeed receiver)
A11 RX2+ (Superspeed receiver)
A12 Ground
B1 Ground
B2 TX2+ (Superspeed transmitter)
B3 TX2- (Superspeed transmitter)
B4 Power
B5 CC2 (orientation configuration information)
B6 Data+ (2.0 speed)
B7 Data- (2.0 speed)
B8 Secondary bus 2
B9 power
B10 RX1- (Superspeed receiver)
B11 RX1+ (Superspeed receiver)
B12 Ground

FireWire

4-pin

Pin Description
1 Twisted-Pair B- (data)
2 Twisted-Pair B+ (data)
3 Twisted-Pair A- (data)
4 Twisted-Pair A+ (data)

6-pin

Pin Description
1 Power
2 Ground
3 Twisted-Pair B- (data)
4 Twisted-Pair B+ (data)
5 Twisted-Pair A- (data)
6 Twisted-Pair A+ (data)

9-pin

Pin Description
1 Twisted-Pair B- (data)
2 Twisted-Pair B+ (data)
3 Twisted-Pair A- (data)
4 Twisted-Pair A+ (data)
5 A shield
6 Ground
7 not used
8 Power
9 B shield

Mini-DVI

Pin Description
1 Data 2+
2 Data 2-
3 Data 1 +
4 Data 1 -
5 Data 0 +
6 Data 0 -
7 Clock +
8 Clock -
9, 10, 11, 12, 13, 14, 15, 16 Digital Signal Ground
17 Power +5V
18 DCC data
19 not used
20 Analog Blue
22 Analog Green
21, 23 not used
24 Analog Red
25 Detect
26 DCC clock
27 not used
28, 30, 32 Digital Signal Ground
29 Analog Horizontal Sync
31 Analog Vertical Sync

DVI

Pin Description
1 Data 2-
2 Data 2+
3 Data 2/4 shield
4 Data 4-
5 Data 4+
6 DDC clock
7 DDC data
8 Analog Vertical Sync
9 Data 1-
10 Data 1+
11 Data 1/3 shield
12 Data 3-
13 Data 3+
14 Power +5V
15 Ground
16 Detect
17 Data 0-
18 Data 0+
19 Data 0/5 shield
20 Data 5-
21 Data 5+
22 Clock shield
23 Clock +
24 Clock -
C1 Analog Red
C2 Analog Green
C3 Analog Blue
C4 Analog Horizontal Sync
C5 Analog Ground

DisplayPort

Pin DisplayPort (Full) Mini DisplayPort
1 Main Lane 0+ (data) Ground
2 Ground Detect
3 Main Lane 0- (data) Main Lane 0- (data)
4 Main Lane 1+ (data) Ground
5 Ground Main Lane 0+ (data)
6 Main Lane 1- (data) Ground
7 Main Lane 2+ (data) Ground
8 Ground Ground
9 Main Lane 2- (data) Main Lane 1+ (data)
10 Main Lane 3+ (data) Main Lane 3+ (data)
11 Ground Main Lane 1- (data)
12 Main Lane 3- (data) Main Lane 3- (data)
13 Ground Ground
14 Ground Ground
15 Auxiliary Channel + Main Lane 2+ (data)
16 Ground Auxiliary Channel +
17 Auxiliary Channel - Main Lane 2- (data)
18 Detect Auxiliary Channel -
19 Return for Power Ground
20 Power Power

HDMI

Pin Type A (Full) Type C (Mini) Type D (Micro)
1 Data2 + Data2 shield detect
2 Data2 shield Data2 + not connected
3 Data2 - Data2 - Data2 +
4 Data1 + Data1 shield Data2 shield
5 Data1 shield Data1 + Data2 -
6 Data1 - Data1 - Data1 +
7 Data0 + Data0 shield Data1 shield
8 Data0 shield Data0 + Data1 -
9 Data0 - Data0 - Data0 +
10 Clock + Clock shield Data0 shield
11 Clock shield Clock + Data0 -
12 Clock - Clock - Clock +
13 control DDC ground Clock shield
14 not connected control Clock -
15 DDC clock DDC clock control
16 DDC data DDC data DDC ground
17 DDC ground HEC+/not connected DDC clock
18 Power +5V Power +5V DDC data
19 detect HEC-/not connected Power +5V

SCART

Pin Description
1 Audio Out right
2 Audio In right
3 Audio Out left (+ Mono)
4 Audio Ground
5 RGB Blue ground
6 Audio In left (+ Mono)
7 RGB Blue in
8 Switch control (Audio/RGB)
9 RGB Green ground
10 Clockpulse out
11 RGB Green in
12 Data out
13 RGB Red ground
14 Data ground
15 RGB Red in/S-Video Chroma (C)
16 Blanking signal
17 Composite Video ground or S-Video Luma ground
18 Blanking signal ground
19 Composite video out
20 Composite video in / S-Video Luma / RGB Sync
21 Ground/shield (chassis)

DB-25

Parallel SCSI

Pin Description
1 Request
2 Message
3 Input/Output
4 Reset
5 Acknowledge
6 Busy
7 not used
8 Data Bus 0
9 not used
10 Data Bus 3
11 Data Bus 5
12 Data Bus 6
13 Data Bus 7
14 not used
15 Control
16 not used
17 Attention
18 not used
19 Select
20 Data Parity
21 Data Bus 1
22 Data Bus 2
23 Data Bus 4
24 not used
25 Termination Power

Parallel/Printer Port

Pin Description
1 Strobe
2 Data Bit 0
3 Data Bit 1
4 Data Bit 2
5 Data Bit 3
6 Data Bit 4
7 Data Bit 5
8 Data Bit 6
9 Data Bit 7
10 Acknowledge
11 Busy
12 Paper Out
13 Select
14 Autofeed
15 Error
16 Reset
17 Select
18 Signal Ground
19 Signal Ground
20 Signal Ground
21 Signal Ground
22 Signal Ground
23 Signal Ground
24 Signal Ground
25 Signal Ground

Serial RS-232 Devices

RS-232 serial device pinouts could vary wildly depending on the specific device in question. Consult pinouts.ru for examples.