- Transmitter and receivers are synchronized of clock.
- Data bits are transmitted with synchronization of clock.
- Character is received at constant Rate.
- Data transfer takes place in block.
- Start and stop bit are required to establish communication of each character.
- Used in high – speed transmission.
- Transmitters and receivers are not synchronized by clock.
- Bit’s of data are transmitted at constant rate.
- Character may arrive at any rate at receiver.
- Data transfer is character oriented.
- Start and stop bits are required to establish communication of each character.
- Used in low – speed transmission.