UTP cabling
- Eight wires make up a UTP cable. Four pairs of wires make up this collection.
- There are two twisted wires in each pair.
- The first wire has a single plastic coating with a colour code, but the second wire has same colour plus a white colour striped coating.
- For the brown wire pair, for instance, one wire has a coating that is entirely brown, while the other wire has a coating that is striped with brown and white.
- A UTP cable is shown in the figure below.
Exactly why are the cables twisted?
- Electromagnetic interference results from the passage of electrical current through copper wires (EMI). The electrical signals travelling via nearby wires, including those that are a part of the same cable, are hampered by EMI.
- It is referred to as the cross talk. Cross talk is eliminated by twisting the wires in pairs.
RJ-45 (UTP cable) connector
- Both the switch port and the NIC include an eight-pin RJ-45 (UTP cable) slot.
- The RJ-45 connection is utilized to link these pins to the wires of a UTP cable.
- The RJ-45 connector has eight physical locations, known as pin positions or simply pins, into which the eight wires of the UTP cable can be inserted.
- These pins make it possible for the ends of copper wires to make contact with NIC or switch port pins.
An RJ-45 connector is shown in the picture below.
Constructing a UTP cable:-
- Pins 1 and 2 are used by a NIC to send data. Using pins 3 and 6, it receives data. A switch makes it do the reverse.
- Data is transmitted from pins 3 and 6 while being received on pins 1 and 2.
- A UTP cable can be created in two different methods depending on the type of end devices.
- The first kind of connection, referred to as a straight-through cable, links two various end devices, such as a PC and a switch.
- The second kind of cable, called a cross-over cable, links two identical end devices, like a PC and a PC or a Switch and a Switch.
- Let's examine both forms of cable's construction in more depth.
Ethernet Straight-through cable
- The conductors in this cable are positioned the same way at both ends.
- The cable's pin 1 at one end is connected to pin 1 at the other end by a wire.
- Pin 2 on one end of the cable is connected to pin 2 on the other end, and so on.
- The wire positions for the straight-through cable on both sides are listed in the following table.
| Side A | Side B |
| Green White | Green White |
| Green | Green |
| Orange White | Orange White |
| Blue | Blue |
| Blue White | Blue White |
| Orange | Orange |
| Brown White | Brown White |
| Brown | Brown |
A straight-through cable is used to connect the following devices.
- PC to Switch
- PC to Hub
- Router to Switch
- Switch to Server
- Hub to Server
Ethernet cross-over cable
- The receiving pins on one side of this cable are connected to the sending pins on the other.
- The cable's pin 1 on one end and pin 3 on the other end are connected by a wire. On the opposite end of the cable, pin 6 is connected to the wire at pin 2. The remaining wires join at both ends in the identical locations.
- The cross-over cable's wire placements on each side are listed in the following table.
| Side A | Side B |
| Green White | Orange White |
| Green | Orange |
| Orange White | Green White |
| Blue | Blue |
| Blue White | Blue White |
| Orange | Green |
| Brown White | Brown White |
| Brown | Brown |
The cross-over cable is used to connect the following devices.
- Two computers
- Two hubs
- A hub to a switch
- A cable modem to a router
- Two router interfaces
