Printers using software (XON/XOFF) handshaking

Computer with DB25 port	Printer with DB25 port
2	3
3	2
7	7
	4-5-6-8

 Computer with DB25 port   Printer with DB25 port
 2                         3
 3                         2
 7                         7
                           4-5-6-8

Computer with DB9 port	Printer with DB25 port
2	2
3	2
5	7
	4-5-6-8

 Computer with DB9 port   Printer with DB25 port
 2                        2
 3                        2
 5                        7
                          4-5-6-8