Table of Contents
Factors on which data cabling depends
- Bandwidth: Greater the bandwidth, higher is the data rate.
- Transmission impairment: Impairments such as noise limits the distance. This impairment is more in twisted pair cables than in coaxial cable than in optical fibers.
- Interference: Interloping due to noise or weather may wipe out a signal. It is caused due to close cable connections.
- Number of receivers: Guided media can be used for a point to point connection or a shared link with multiple attachments. Due to many attachments, the data rate decreases due to distortion and noise.
Twisted Pair Cable
- It consists of two insulated copper wires arranged in regular spiral fashion.
- A number of these pairs are bundled together into a cable by wrapping them into a though protective sheath.
- Twisting generally decreases the cross-talk interference.
- Twisted length typically varies from 2 to 6 inches. It has a thickness range of 0.016 to 0.036 inches.
- Mostly used in data cabling of telephone lines for offices with individual telephone sets.
- Can be used to connect all the telephones in a building.
- Also used for LAN supporting PCs.
- It is also used in DSL lines, used in telephone companies to achieve higher data rate.
- It can be used to transmit both digital and analog signal.
- It consists of a single inner wire conductor surrounded by a hollow cylinder outside. The inner conductor is held in place by either regularly spaced insulation rings or a solid dielectric material.
- Because of the shield, it is much less susceptible to interference and crosstalk than twisted pair cable.
- It is widely used in television distribution. Long distance telephone transmission, short-run computer system links and LANs.
- This is also used for both analog and digital transmission.
- It has higher data rate because of its frequency.
- It is much less susceptible to interference.
- It is mostly affected by thermal noise and intermodulation noise.
- Amplifiers and repeaters are used for long-distance communication.
- It is a thin flexible medium capable of conducting an optical ray. It is cylindrical in shape. It has three sections which are concentric.
- This is mostly used for data cabling for long distance communication. The reasons are listed below:
- Small size and lighter weight
- Lower noise
- Electromagnetic isolation
- Greater repeater spacing
Categories of optical fibers are as follows
- Long Haul Trunks: These routes in an average of about 900 miles in length multiplexing 20,000 to 60,000 voice channels. It is an economic approach to connect trunk routes.
- Metropolitan Trunks: This has an average length of 7.8 miles and around 1 lac voice channels in a trunk group. Most facilities are installed in underground conduits and are repeater less joining telephone exchanges in a metropolis.
- Rural Exchange Trunks: Circuit lengths range from 25 to 100 miles that link towns and villages. Have less than 5000 voice channels.
- Subscriber loops: Fibers run directly from thecentralr exchange to the destination. These networks are capable of handling voice, data, images and videos.
- Local Area Network (LAN): A typical optical fiber LAN id FDDI (Fiber Distributed Data Interference) is mostly used for data cabling.