Cables

Types

  • Cat 6 - 10 Gbps. 2x Performance of Cat 5 & 5e - frequency up to 250 MHz
  • Cat 5e - 1Gbps
  • Cat 5 - 100MBPs

Conductor

Shielding

  • Indoor cables must overcome interference from other wires. So shielding is needed.
  • Unshielded cables are generally ok for outdoor use.

Types

  • U/UTP (Unshielded Twisted Pair) means the cable consists of 4 unshielded twisted pairs and no outer shielding.
  • CAT6A F/UTP (Foiled Unshielded Twisted Pair) means the cable consists of 4 unshielded twisted pairs however it contains an outer foil shield.
  • S/FTP (screened/foiled twisted pair) cable, normally a CAT7 cable that has four individually shielded pairs and an outer screen braid around all four pairs.

Crimping

Wire-terminal matching

T-568B is most commonly used.

                 T-568B                         T-568A
       --------------------------      ------------------------
Pin    Color             RJ-45 use      Color          RJ-45 use
---    -------------     --------      -------------   --------
 1     Orange Stripe     Tx+           Green Stripe    Rx+
 2     Orange            Tx-           Green           Rx-
 3     Green Stripe      Rx+           Orange Stripe   Tx+
 4     Blue              Not Used      Blue            Not Used
 5     Blue Stripe       Not Used      Blue Stripe     Not Used
 6     Green             Rx-           Orange          Tx-
 7     Brown Stripe      Not Used      Brown Stripe    Not Used
 8     Brown             Not Used      Brown           Not Used
  • The other two colors (blue and brown) may be used for a second Ethernet line or for phone connections.

Straight vs cross-over ends

  • Straight-through cable, as its name suggests, connects pin 1 to pin 1, pin 2 to pin 2, pin 3 to pin 3, and pin 6 to pin 6.
  • Cross-over cables are used to connect TX+ to RX+, and TX- to RX-, which connects pin 1 to pin 3, pin 2 to pin 6, pin 3 to pin 1 and pin 6 to pin 2.

RJ (Registered jack) Terminals

  • RJ-11 is a 6-position, 4-conductor jack used in telephone wiring
  • RJ-45 is used for LAN.