📖 IT Bible

Twisted Pair Cable

  • most common type of cabling used for connecting computing devices
  • it features pairs of copper wires that are twisted together

Duplex Communication - concept that information can flow in both directions across the cable

Simplex Communication - unidirectional

  • Unshielded twisted pair (UTP) - The most common and least expensive type of Ethernet cable found in business and home networks. UTP cables offer very basic protection against EMI, RFI, and crosstalk interference. 

  • Shielded twisted pair (STP) - Used in environments where electromagnetic interference (EMI), radio frequency interference (RFI), and crosstalk with nearby cables have been identified as a problem for network communications. An STP cable uses a braided aluminum and/or copper shielding to encase the four twisted pairs underneath the outer jacket. 

  • Foiled twisted pair (FTP) - Also used in environments where EMI, RFI, and crosstalk are a problem. An FTP cable uses a thin foil shield that wraps around the bundle of twisted pair wires underneath the outer jacket.

Straight-through cable key:

  • Computers and routers use:
    • Pins 1 & 2 - Orange wires for sending data
    • Pins 3 & 6 - Green wires for receiving data 
  • Hubs and switches use:
    • Pins 1 & 2 - Green wires for sending data
    • Pins 3 & 6 - Orange wires for receiving da

Crossover cable key:

  • Endpoint 1 of the Ethernet cable:
    • Pins 1 & 2 - Green wires for sending data
    • Pins 3 & 6 - Orange wires for receiving data 
  • Endpoint 2 of the Ethernet cable:
    • Pins 1 & 2 - Orange wires for sending data
    • Pins 3 & 6 - Green wires for receiving data