Physical Layer 1

This layer deals with the physical aspects of the media being used to transmit the data. The electrical, mechanical, procedural and functional means This defines things like pinouts, electrical characteristics, modulation and encoding of data bits on carrier signals. It ensures bit synchronisation and places the binary pattern that it receives into a receive buffer. Once it decodes the bit stream, the physical layer notifies the data link layer that a frame has been received and passes it up. Examples of specifications include:

• V.24
• V.35
• EIA/TIA-232
• EIA/TIA-449
• FDDI
• 802.3
• 802.5
• Ethernet
• RJ45
• NRZ
• NRZI