Oki ML490 Maintenance Manual - Page 131

2.3.2 Mode b X-ON, X-OFF Received one character? No Yes Is DSR valid? No Yes DSR High? No Yes Buffer overflow? Yes No Error? No error Store the received character in buffer. Parity error Store 40 H in buffer. Is the printer in DESELECT state or is the paper low? No Is remaining buffer space < 256? No Has 200 ms elapsed after sending DC3 is turned on or has 1 second elapsed? Yes No Ready to send? Yes Send DC1. Yes Yes Yes No Is remaining buffer space > 256 during receive time out? No No Ready to send? Yes Send DC3. 42114101 Rev.1 Yes Printer busy? No Output one character to printer. Figure C-3 131 /