Basics of data transfer & Network Cabling

Transmission and Network Cabling

Cables play vital role in networking domain. A medium of data transmission from one point to another point.

Types of CABLES, CONVERTERS

Co-axial Cable:

what consists inside a coaxial cable? There is a little copper conductor which is surrounded by one white insulator, and then there is another conductor. There is different type of metal and aluminum foil for second conductor. And all are wrapped with polyvinyl chloride or plastic jacket. It is called coax because those two conductors, the one copper in the middle, and the big metal sheathing around that, both of those conductors share the same center point so as they have same axis and called co-axial. 

There are different types of coaxial cable they can be called as RG (Radio Grade) type and there are many RG rating cables such as RG-58, RG-59, RG-6, RG-11, etc. All these co-axial cables come with connectors known as RF connector. All the connectors differ by its inner diameter of the outer conductor and as 3. 5mm, 2. 4mm, 1.85mm and 1 mm. Presently co-axial cables were being used at Modems and TV Cables. 

Twisted pair cable:

It is called twisted pair cable because it is always in pairs and each pair is twisted around itself. The twisting allows the signal to propagate further down a piece of copper wire. Twisted pair cabling was originally invented back in early 1970s for telephone systems and twisted pair cabling has become the most common form of cabling in networking domain. 

The twisted pair cable is available in two variants i.e. Shielded, Unshielded twisted pair cable. And one of the big improvements that we see with unshielded twisted pair is its ability to work with faster and faster networks.

CAT Cable (Unshielded Twisted Pair or UTP) 

A standard UTP cable consists of 100-ohm copper cable made with 2-1800 unshielded twisted pairs protected by an outer jacket. It is used for LAN networks. 

Depending on the certain speed and bandwidth of networks, the unshielded twisted pair cables were categorized or rated as Category and called as CAT 1, CAT 2, CAT 3, CAT 6, CAT 7 etc. The older telephone cable, we had used, has a Cat rating called Cat 1. So these different cat numbers have different speeds for data transmission. But in case of Cat 7 cable it is originally shielded twisted pair cable. Each individual pair has its own customized shielding around it, to separate one from another. 

Cables are standardized by EIA/TIA [National Industry Association/ Telecommunication Industry Association] and NEC [National Electrical code] like wise:

1.Copper

2.Copper covered steel.

3.copper covered other.

Basically UTP cables are used for ethernet with RJ 45 connector. These cable are used for the computer networking. Its a 100 ohm copper cable consisting up to 1500+ (1800) unshielded twisted pairing. It have no metallic shield still, its not protected from the electrical interference.   

Capacity Of Data transfer at the cables -

• CAT1: up to 1 Mb/s for voice communication only, traditional telephone connection
• CAT2: Up to 4 Mb/s used for token ring networks.
• CAT3: 10Mb/s used for ethernet connectivity
• CAT4: up to 16 Mb/s used for token ring networks.
• CAT5: 100Mb/s used for ethernet and can support up to 100 meters of connectivity capacity. 
• CAT5e: up to 1 Gb/s used for ethernet, fast ethernet and gigabit ethernet.
• CAT6: up to 10Gb/s used for gigabit ethernet and 10G ethernet and up to 55 mtr capacity 
• CAT6a: up to 10Gb/s used for gigabit ethernet and 10G ethernet and up to 55 mtr capacity 
• CAT7: up to 10Gb/s used for gigabit ethernet and 10G ethernet and up to 55 mtr capacity 

RJ45 connector/Plug

RJ 45 pin Description:-

  Pin No.||       Description ||

       1             Tx (+)

       2             Tx (-)

       3             Rx (+)

       4             Not Use

       5             Not Use

       6             Rx (-)

       7             Not Use

       8             Not Use.

                                                          UTP cable cat-6

#The UTP cable is crimped in to RJ45 by its colour code.

#The patch cord used to form two types according to compatibility of communication by using colour codes: Straight through and cross over.

NB: For Same Device type Cross over cable used.

       For different type device Straight through cable is used.

Colour Code For Straight and Cross cable

RJ45 modular plug

 

RJ-45 Crimping tool

UTP-6 Keystone jack or Plug

Standard Rj colour code

Standard patch cord for LAN connectivity

 

Key points to remember:

• Same Device [Connected by Cross over]
• Different Device [Connected by Straight through]

Fiber Optic Cable / Optical Fibre Cable (OFC):-

The optical fiber cable contains the fiber optics to carry out signal. The signal or data communication is basically due to the LED [Light emitting Diode] or Laser.

It uses multiplexing technology which maximizes the capacity of transmission .

Different types of OFC are used as: multi core, multi mode and single mode.

 

The Single-mode cable is designed to be used with lasers. It has a much thinner piece of fibre inside it and the cladding is tighter. It can transmit longer distances.

 

We have to note one important thing that multimode is almost always orange, and single mode is always yellow in colour. 

Similarly there are different types of connectors for Ofc is being used such as ST, SC, FC, LC, MT-RJ, etc.

 

Single mode

Multimode-multicore/outdoor use only

Different types of ofc  (Optical Fibre Cable) Connectors.

OFC cable SPLICING .

 

CABLE SPLICING machine.

splicing machine

SPLICING of cable is needed when there a joining comes. It is to join regular  and buried in the ground or may be inside Distribution Box. It is needed to join two short cables to one cable for communication. Hence there are two types of Splicing i.e. 1.Mechanical 2.Fusion Splicing.

1.Mechanical Splicing is done by mechanically, holding two ends together and wrapped inside a  joint.

2.Fusion Splicing is done by two fiber cores are welded or fused together by heat, but it costs higher.

After Splicing of the OFC Cable  it is being tested by OTDR Machine for signal strength and loss status.

OTDR 

TYPICAL DISTRIBUTION BOX

OTDR: Optical Time-Domain Reflecto meter

It is an Opto-electronics device used to detect any problems on the fibre links. To check the health of the signal communication through fibre.

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CABLE (DB9-RJ45):- 

Basically used for Configuration of Routers and Switches we use CONSOLE CABLE ( DB9 to RJ45).

standard console cable

CABLE X.21 (DB60-DB15):- 

This cable is used for Cisco access servers access pro cards and for higher family of routers i.e. 7000,4000,3600 etc. used for connecting devices.

fig: standard DB60-DB15 cable

Ethernet to fiber converter:-

The Media Converter complies with IEEE 802.3z, IEEE 802.3AB Standards. It is designed to convert data signal between 10/100Base-T and 100Base-FX Fast Ethernet. It supports 10/100Base-T and 100Base-FX applications. The Converter is equipped with 2 single fiber optic connectors (One for transmitting-TX and another for receiving-RX) and one RJ-45 Jack and one external power supply receptacle. Six LED indicators are built-in for easy diagnosing and monitoring the status of power, Unshielded Twisted Paired (UTP) Link, UTP Activity, Fiber Link, Fiber Activity, Full duplex and data rates. It can be configured automatically for Full Duplex or Half Duplex operation.

SFP Module:

The small form factor pluggable (SFP) is a network interface module used for both communication of data and voice. It comes for SFP port of Routers and Switches.

It comes with different speeds such as Fast Ethernet to Gib Ethernet. 

Type of connectivity:- 

RJ45 SFP Module with Cat6 Cable, Fibre SFP Module with Fibre optic cable.

It links the router and switch in a network. Modern switches are designed to have two or more SFP modules in built

One sample module is illustrated as below;

In case of Cables, sometime all the lying cables should be managed well or should be kept in structured way to avoid any interference in signal and data. Before installation of cables, they should be measured well. 

In Data Centre or large networks sometimes cable management is a complex task. It can be Horizontal cable management, vertical cable management, Patch panel, cable tray system, various clamps, tags etc.

-DR