M-S Cash Drawer 7193 - Manual (Page 51)

7193 Owner’s Guide Communication
May 1996
XON/XOFF Protocol
The XON/XOFF characters coordinate the information transfer between the
printer and the host system. The printer sends an XON character when it is ready
to receive data and it sends an XOFF character when it cannot accept any more
data. The software on the host system must monitor the communication link as
shown in the following flowchart in order to send data at the appropriate times.
Was an XON
or XOFF charactor
last received?
XON
11 HEX
Send Data
13 HEX
XOFF
Wait for
XON character
XON character = Hex 11.
XOFF character = Hex 13.
DTR/DSR Protocol
The DTR signal is used to control data transmission to the printer. It is driven
low when the printer is ready to recieve data and driven high when it cannot
accept any more data. Data is transmitted from the printer after it confirms that
the DSR signal is low.
Is DTR
High or Low
Low
Send Data
High
Wait for
DTR to Go Low