C – 6
Figure C-2-3
X-ON, X-OFF
Received one
character?
Yes
Is DSR valid?
No
Buffer overflow?
Error?
Parity error
No error
Store the received
character in buffer.
Is the
printer in DESELECT
state or is the paper
low?
No
No
Yes
Yes
No
DSR High?
Yes
Store 40 H in buffer.
Yes
Yes
No
Yes
Is remaining
buffer space < 256?
Yes
No
Printer busy?
No
Output one character to printer.
No
Yes
No
Has 200 ms
elapsed after sending DC3 is
turned on or has 1 second
elapsed?
Is remaining
buffer space > 256 during
receive time out?
Ready to send?
Ready to send?
Yes
Send DC1. Send DC3.
No
Yes
No
2.3.2 Mode b