Synchronous

• Existing or occurring at the same time
• Synchronous transmissions is controlled by an external clock
• Constant/continuous connection
• Applications such as: Skype, FaceTime, chat rooms, online games use synchronous data transmission
• Messages flow both ways
• Two way communication at the same time
• Continuous – no start and stop bit

Asynchronous

• Controlled by special signals sent along the transmission medium
• Sent in regular intervals sending data one after another
• Non continuous data transmission
• Used by services such as: Email, Snapchat, WhatsApp, SMS messaging, websites
• Don’t need to establish a connection
• An event is used to trigger connection and alert the user
• One way communication
• Provides you with a higher availability
• Internet is asynchronous