Windows Command Prompt

Ports and Cables on the A+ Exam

Ports and Cables

There are several types of ports and cable you should be familiar with for the exam.

USB

Universal Serial Bus, or USB, is the new standard for peripheral connection to PCs. USB is a jack of all trades – handling a wide variety of input devices and storage devices including external hard drives, keyboards, mice, scanners, printers, PDAs, digital cameras, USB devices range from scanners to printers to storage devices.

Because of the ability to handle multiple types of devices easily, systems are moving towards also complete ubiquity of USB ports and devices are moving toward using only USB for connectivity. I recently bought a system where its only input ports are USB and Firewire.

There are two standard versions for USB: 1.1 and 2.0. 2.0 is backward compatible with 1.1 (it supports 1.1 devices) but has a much faster data transfer speed. USB 1.1 supports data transfer up to 12 mbps while USB 2.0 supports data transfer speeds of up to 480 Mbits per second. USB 3.0 will bring us transfer speeds of up to 4.8 Gbits per second. Each PC supports up to 127 devices.

Other Types of Ports and Cables

DB-9

DB-9 is a standard connection for a COM cable (serial cable). Contains 9 pins.

DB-25

DB-25 is the other standard connection for Serial cables. Serial communications only use 9 of the available 25 pins.

Parallel (IEEE 1284)

A 25 pin connector on the computer side and a 36 pin connector on the printer side. Most printers are moving to a standard Ethernet or USB connection.

RJ-11 Connector
RJ-11

RJ-11 is a standard telephone type connection. It is 4 or 6 wire and some networking equipment has used RJ-11, though RJ-45 is more common.

RJ-45

RJ-45 is the most popular network cable/connection type. RJ-45 is similar to the RJ-11 type connector, though it has 8 wires.

BNC

BNC is a type of network connection most commonly used in 10 Base 2 networks. BNC is primarily used with a coaxial cable.

PS2/MINI-DIN

PS2 is a standard developed by IBM for keyboards, mice, and input devices. Uses a DIN connection with 6 pins.

IEEE 1394

IEEE 1394 is the standard for what is commonly referred to as “Fire wire”. Apple Computer coined the term when they began adding Fire wire ports to their Macintosh computers.

IEEE 1394, or Firewire, is a high speed connector for data intensive applications such as video editing or external storage devices. Standard Firewire supports up to 400 Mbits per second transfer while newer Firewire/800 supports 800 Mbits/second. Each PC can support up to 63 Firewire devices.