The Differences Between Synchronous and Asynchronous Communications

Explain the differences between:

a. Synchronous and asynchronous communications

Both of these forms of communication are a means of transmitting data. The difference is in the format that the data is transmitted.

Synchronous Mode

Transmissions that are timed by a clocking signal and occur with equal time intervals between them. Synchronous mode does not require a start and stop codes as in asynchronous mode. See also Asynchronous Mode.

Asynchronous Mode

Not synchronous. A way to send transmissions by starting and stopping transmissions with a code rather than sending transmissions at specific time intervals as in synchronous mode. Asynchronous communication devices do not have to be synchronized with a clocking signal, which is required with synchronous transmission. Also frequently referred to as ATM or Asynchronous Transfer Mode. See also Synchronous Mode.

Asynchronous communications is the method of communications most widely used for PC communication and is commonly used for e-mail applications, Internet access, and asynchronous PC-to-PC communications. Through asynchronous communications, data is transmitted one byte at a time with each byte containing one start bit, eight data bits, and one stop bit, thus yielding a total of ten bits. With asynchronous communications, there is a high amount of overhead because every byte sent contains two extra bits (the start and stop bits) and therefore a substantial loss of performance.

Synchronous communications is the more efficient method of communications. CQ’s connectivity solutions communicate through the synchronous method of communications.

Through synchronous communications, data is transmitted as frames of large data blocks rather than bulky individual bytes. One advantage of synchronous is that control information is easily inserted at the beginning and end of each