Star Micronics 150 User Manual
Programmer's Guide
PcOS Series 150
Communications
Serial Port
12/14/99
Rev G
Page 119
Serial
Communications
port
Data
Buffer filling up
Buffer emptying
Data
Select key
Printer
control
control
software
Print
buffer
256 - 6K
Serial Port Flow Control
XON/XOFF
RTS -> Request to send
DTR -> Data terminal ready
data in
Serial
data out
(Not used for
flow control)
DTR
RTS
Send
XOFF
Send
XON
Send
XON or XOFF
Inquire
commands
Data
High
speed
FIFO
ENQ response
Data
ENQ
Proc.
Figure 21 Serial port flow control XON/XOFF