Data Communications
There are two main issue to consider in data communications:
1.the interface standard(e.g. the physical wiring & voltage consideration)
2.the software protocol(e.g. the order & type of characters being transmitted.
Format of Data Communication Message:
For a simple asynchoronous system such as RS232, it is common practice to send one character at a time.The format of a typical character frame is indicated in figure 1.1
Figure :1.1 Format of a typical serial asynchronous Data character
Initially the data communications link is the idle state,lthe line is in the mark state,held to a constant negative voltage.
The parity bit included at the end of the character is effectively a fingerprint of the character to enable the receiver to identity whether any errors have occurred in the transmission. Example: even parity means that the total number of logic 1 bits in the data together with the associated parity bit must be an even number.
The optional settings for asynchronous transmission of characters are:
Start Bits 1
Data Bits 5,6,7,8
Parity Bits even,odd,mark,space or none
stop Bits 1,2
There are two main issue to consider in data communications:
1.the interface standard(e.g. the physical wiring & voltage consideration)
2.the software protocol(e.g. the order & type of characters being transmitted.
Format of Data Communication Message:
For a simple asynchoronous system such as RS232, it is common practice to send one character at a time.The format of a typical character frame is indicated in figure 1.1
Figure :1.1 Format of a typical serial asynchronous Data character
Initially the data communications link is the idle state,lthe line is in the mark state,held to a constant negative voltage.
The parity bit included at the end of the character is effectively a fingerprint of the character to enable the receiver to identity whether any errors have occurred in the transmission. Example: even parity means that the total number of logic 1 bits in the data together with the associated parity bit must be an even number.
The optional settings for asynchronous transmission of characters are:
Start Bits 1
Data Bits 5,6,7,8
Parity Bits even,odd,mark,space or none
stop Bits 1,2
