Xon/Xoff is a software based flow control method.  Its very simple and is designed for ASCII based comms links.  When enabled the following 2 bytes/characters are sent by the pother side to disable and enable you transmitting:

Xoff = Ctrl-S = 0x13 = You must stop sending data

Xon = Ctrl-Q = 0x11 = You can start sending data again

When transferrign binary data you have the problem that your binary data may contain these bytes values.  You can work around that by detecting and converting them (e.g. to 2specail byte values say) before you transmit and then converting them back at the far end, or simply use and encoding method to encode your data to ASCII.


We benefit hugely from resources on the web so we decided we should try and give back some of our knowledge and resources to the community by opening up many of our company’s internal notes and libraries through mini sites like this. We hope you find the site helpful.
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