The physical layer is the lower most layer in OSI model which deal with raw data transmission. Physical layer provides electrical, mechanical, functional and procedural means to activate, maintain and deactivate physical connections for bit transmission between data link entities.
Physical Layer Defines:
Physical Layer Defines:
Mechanical
Medium
A transmission medium is any material substance which can propagate waves or energy. The media can be broadly classified as Guided and unguided.
Guided: Copper, Fiber
Unguided: Infrared, radio, Microwave
Connectors
An electrical connector is a device for joining electrical circuits together.
Ex: DB25, DB9, DIN, RJ-45
A transmission medium is any material substance which can propagate waves or energy. The media can be broadly classified as Guided and unguided.
Guided: Copper, Fiber
Unguided: Infrared, radio, Microwave
Connectors
An electrical connector is a device for joining electrical circuits together.
Ex: DB25, DB9, DIN, RJ-45
Topology:
The physical or logical shape of the network.
Ex: Star, Ring, Bus
Electrical
Line Coding
The waveform pattern of voltage or current used to represent the 1s and 0s of a digital signal on a transmission link is called line encoding.
Ex: NRZ, 2B1Q, 4B45B, AMI
Modulation
Process by which an information signal is used to modify some characteristic of a higher frequency wave known as a carrier.
Ex: AM, FM, FSK, PCM
Multiplexing
Multiplexing is a term used to refer to a process where multiple analog message signals or digital data streams are combined into one signal.
Ex: TDM, FDM, CDMA, WDM
Procedural
The waveform pattern of voltage or current used to represent the 1s and 0s of a digital signal on a transmission link is called line encoding.
Ex: NRZ, 2B1Q, 4B45B, AMI
Modulation
Process by which an information signal is used to modify some characteristic of a higher frequency wave known as a carrier.
Ex: AM, FM, FSK, PCM
Multiplexing
Multiplexing is a term used to refer to a process where multiple analog message signals or digital data streams are combined into one signal.
Ex: TDM, FDM, CDMA, WDM
Procedural
Transmission Mode
Synchronous or Asynchronous
Synchronous or Asynchronous
Transmission Direction
Simplex, Half Duplex or Full Duplex
Simplex, Half Duplex or Full Duplex
Communication Mode
Serial or Parallel
Serial or Parallel
Line Configuration
Point-Point, multipoint, or point-multipoint
Error Control
Parity bits and CRC
Parity bits and CRC
Media Control
Carrier Sensing and Collision detections
Carrier Sensing and Collision detections
Physical Layer Protocols:
X.21, X.21 bis, V.90, V.92
RS232, EIA442, EIA423, RS449, RS485
ISDN, B-ISDN, DSL, xDSL
SDH/SONET, T1/E1
10BASE-T, 10BASE2, 10BASE5, 100BASE-TX, 100BASE-FX, 100BASE-T, 1000BASE-T, 1000BASE-SX physical layers
IrDA, Wi-Fi, GSM, CDMA, Blutooth physical layers
