Device Connectors and Cables - CompTIA A+ 220-801: 1.11

SCSI interfaces

PS/2 connector

• 6-pin mini DIN
• Mouse and keyboard
• PC System Design Guide standard colors
• Named after the IBM PS/2
• Circa 1987

• Replaced by USB
• 25 years of legacy devices

Parallel Connector

• Used mostly by legacy printers
• But can be used by other devices
• DB-25 port
• 25 pins, wide interface

• Centronics connector
• 36 pins, locking mechanism

• Legacy use
•  Most devices today are USB-based

Serial connector

• Seen mostly in legacy hardware
• Modem, mouse
• Used in management of infrastructure devices
• 9-pin and 25-pin connectors are common
• 25-pin was old school

• Size is similar to a VGA port
• DE-9 instead of DE-15

• Pins are male on the computer interface
• Parallel and video is female

RJ-45 

• RJ-45 (Registered Jack)
• Usually Ethernet connection
• 8P8C
• 8 position, 8 conductor
• Technically not RJ-45
• RJ refers to the wiring and not just the physical connection
• Almost universally called the wrong thing

RJ-11

• RJ-11 (Registered Jack)
• Usually telephone connection
• 6P2C
• 6 position, 2 conductor
• Some RJ standards use the same physical interface
• but different wiring
• 6P4C, 6P6C, ect

Audio Ports

• 3.5mm (1/8") TRS plugs
• Tip/Ring/Sleeve
• Color standard not always followed
• Check your connection when working in tight quarters