Synchronous Transmission

In this transmission ,bits are transmitted at fixed rate. The transmitter and receiver both use the same clock signals for synchronisation.
• Allows characters to be sent down the line without start-stop bits.
• Allows data to be send as a multi-word blocks.
• Uses a group of synchronisation bits, which is placed, at the beginning and at the end of each block to maintain synchronisation.
• Timing determined by a MODEM
Advantage: Transmission is faster because by removing the start and stop bits, many data words can be transmitted per second.
Disadvantage: The synchronous device is more expensive to build as it must be smart enough to differentiate between the actual data and the special synchronous characters.