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difference between synchronous and asynchrounous ?

hello,

what is the difference between synchronous serial and asynchronous serial?

thanks.

1 ACCEPTED SOLUTION

Accepted Solutions

Re: difference between synchronous and asynchrounous ?

hi here both are the types of the serial communication... you can get more information for this link:http://www.erg.abdn.ac.uk/users/gorry/eg2069/async.html

rate this post if it helps

regards

Devang

3 REPLIES

Re: difference between synchronous and asynchrounous ?

hi here both are the types of the serial communication... you can get more information for this link:http://www.erg.abdn.ac.uk/users/gorry/eg2069/async.html

rate this post if it helps

regards

Devang

Green

Re: difference between synchronous and asynchrounous ?

Synchronous indicates that the communicating devices are using a common, active clock.

Asynchronous indicates that there is no common clock, and so some method must be used to let the receiver know that information is arriving, and where the valid bits of information are in the transmission.

In Ethernet, this is done with a preamble, which is initially a string of 64 alternating zeros and ones. This sequence announces that traffic is arriving, and give the receiver "the rhythm" to sync up.

In RS232, it's a simple "Start Bit;" it wakes up the receiver, and tells it to begin paying attention to the line transitions indicating marks & spaces.

In a synchronous communication, the clock is always present, payload areas are defined, as well as administrative areas (like framing and possibly in-band messages). Every clock cycle has a meaning and a purpose.

Because of the need to put in synchronizing elements, asynchronous communications have more overhead.

For example, two 64K lines, one sync, one async, the async line will have more transmission overhead (less payload for the time measured) because of the synchronizing elements.

Hope this helps,

Good Luck

Scott

Bronze

Re: difference between synchronous and asynchrounous ?

both are serial communication method

Synchronous - Requied clock for communication

Asynchronous- Not required clock for communication.

Let me give you example, 1 )when you connected two device back to back in syn mode , it have same clocking required in both side.

2) when you connected two devices back to back , does not requied clocking shoud be same.

-Minu

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