Knowledge Base FAQ Item #3100010

Q3100010: What is flow control?

In many scenario's, it is necessary for the transmitting device to know whether the receiving device is ready to receive information. You might, for example, be sending data to a printer, and the speed of communication may be faster than the speed of the printer. The printer will need to be able to stop the computer from sending any more chatacters until it is ready to receive them. Similary, you may be sending data from one computer to another, and the second computer cannot process the data as fast as it is coming in.

In both cases, information must be sent back from receiving device to the sending device to indicate whether it is ready. This is known as 'Flow Control'. There are two types of Flow Control: Hardware Flow Control and Software Flow Control.