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I need to connect a VSF display to a computer. The VSF datasheet has this pin out specifications (

EIN-Host Busy
EOUT-Module Busy

But I can not understand how to connect it to a RS232 serial port. Seems that DIN=TD and DOUT=RD but I can understand how to connect the Host Bus/Module Busy. In the datasheet I found this:

Link EIN and EOUT for XON/XOFF

But I can not understand. Isn't XON/XOFF a software flow contol?

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up vote 2 down vote accepted

You can either use hardware handshake or software handshake. For bidirectional hardware handshake, you need two extra lines (one in, one out). For XON/XOFF software handshake, no extra lines are needed. You then connect the handshake lines EIN=EOUT to indicate "always ready".

Software handshake (software flow control) uses special control bytes XON (Ctrl+Q) and XOFF (Ctrl+S) to resume or suspend the data flow.

If your cabling and the device connector allow, you should use hardware handshake. It takes more lines but allows higher speed and will lead to fewer errors.

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Ok, now I understand "link EIN and EOUT", this mean to short these two pins... But If I want to use hardware handshake where do you think EIN-EOUT must be connected to? RS232 has RTS or CTS but seems to be the opposite of "Host Busy","Module Busy". – Tobia Sep 24 '13 at 6:55

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