6.2.3 RS-232C loopback test
After connector wiring as shown tn the figure, turn on the test mode.
The printer will receive data that has been transmitted by printer itself
and the test of receiving and transmitting data will be performed.
Fig. Loopback test
6.2.4 RS-232C protocol
(1) X-ON/X-OFF system (see figure)
This is a control system in which the data transmission request
signal (X-ON (11H) code) and the data transmission stop request
signal (X-OFF (13H) code) are output.
Requirements of output of X-ON code:
• When the power is switched to ON
• When the remaining buffer is less than 2K bytes, and after
outputting the X-OFF, the remaining buffer is more than 4K bytes
Requirements of output of X-OFF code:
• When a printer error occurs
• When the remaining buffer is less than 2K bytes
6-7
