Parallel Port Status Signals When An Error Occurs; Compatible Timing Specification - Citizen CL-E720DT Technical Manual

Chapter 2 Operating Principles
2-4. Interface

(3) Parallel port status signals when an error occurs

The following table shows the status signal change when an error occurs.
Under the specifications for this bi-directional parallel interface, the parallel port status signals
when an error occurs are, as shown below, partially processed differently than with Compatible
mode used up till now. When bi-directional parallel interface is on in the setting menu, even if a
printer error has occurred, the BUSY signal line is not active ("High").
Error
Paper end
Error other than paper end
• Head open
• Other
Conditions for Busy


(4) Compatible timing specification

[When power is on] (Timing to go on-line)
Reset
BUSY
ACK
SELECT
CL-E720DT
Compatible mode
L  H
Busy:
L  H
PError:
H  L
Select:
H  L
Fault:
L  H
Busy:
PError: L unchanged
H  L
Select:
H  L
Fault:
• Receive buffer full
• Data being read
• Error
Power On
2-58