Question

Explain in short six characteritics of Transmission Media.

List any six characteristics of transmission media.

Explain the following characteristic of transmission media:

Bandwidth

Explain the following characteristic of transmission media:

Band usage

Explain the following characteristic of transmission media:

Attenuation

Explain the following characteristic of transmission media:

E.M.I.

Answer 1

Characteristics of Transmission Media are:

(a) Bandwidth:

• Bandwidth refers to the capacity of a communication medium to carry data.
• Data transmission rate is defined as the number of bits sent per second.
• The bandwidth of a cable is influenced by the length of the cable.
• A shorter cable can support higher bandwidth than a longer one; therefore, maximum cable lengths are specified for different cable designs.
• If these limits are exceeded, high-frequency signals may weaken, leading to errors in data transmission.

(b) Band usage:

1. The bandwidth is shared so that maximum usage is obtained.
2. There are two transmission modes, base band and broad band transmissions.
3. Base band devotes the entire capacity of the medium to one communication channel.
4. Broad band enables two or more communication channels to share the bandwidth of
   communication medium.
5. The base band and broad band transmission modes are shown in following figure
   

 (c) Attenuation:

• Attenuation refers to the extent to which a signal loses strength as it travels through a transmission medium.
• When a signal passes through a medium, a portion of the signal is absorbed, causing the signal to become weaker.
• Attenuation helps determine the maximum cable length; when the signal strength drops below a certain level, noise may appear at the receiving end.
• Repeaters are used to restore and strengthen weakened signals.

(d) Immunity from electromagnetic interference (EMI):

• Electromagnetic interference (EMI) refers to external electromagnetic noise that disturbs signals traveling through a transmission medium.
• EMI disrupts signal transmission and makes it difficult for computers to interpret the received signals correctly.
• A common example of electromagnetic interference is crosstalk, which occurs when a signal from one wire is unintentionally received by another wire.
• In computer networks, a large number of cables are placed close to each other, making crosstalk a major issue in such networks.

(e) Cost of media:

• One major factor in purchase decision of any networking  component is its cost.
• For a new fast technology, cost is also more expensive.
• Decision depends upon application and standard of the  resources.
• Therefore, the network designer must settle for something, which is cheaper and robust.

(f) Installation requirement:

• Some transmission media requires skilled labour to install. This increases cost of network and it may cause certain delay.
• Before installation we need to prepare actual physical layout of network.