5-52
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Communication Timing
ENQ
ENQ
NAK
ETX
STX
ACK ACK
ENQ
ETX
STX
ENQ
ETX
STX
ENQ
ACK ACK
ACK
ACK
NAK
External
device
IJ printer
Print start signal
Readiness
for reception
(No signal output)
Not ready
for
reception
Ready for
reception
Printing
operation
A
B
C
C
On-line
Off-line
(a)
(b)
(c)
(d)
A
B
C
5.5 Communication Timing
5.5.1 Signal Timing
(1) In overwrite-protected mode
(a) When the IJ printer is off-line
●
The NAK code is transmitted in response to an ENQ code reception from the outside.
(b) When the IJ printer is on-line
When transmitting printing only
●
Transmission data is received from the external device. When the received data is not in error, the
ACK code is transmitted and the "not ready for reception" state prevails.
●
To switch from the "not ready for reception" state to the "ready for reception" state, perform one of
the following procedures.
1) Perform a printing operation once.
2) Transmit the DC2 (retransmission) code to the IJ printer.
3) Press the Comm On/Off buttun to enter the off-line mode, and then switch back to the on-line
mode.
●
If the data transmitted from the external device is in error, the NAK code is transmitted after receipt
of the ETX code.
Since the "ready for reception" state is maintained in this instance, retransmit the data beginning.
When transmitting print conditions, user pattern characters, and print data recall
●
When the data received from the external device is not in error, the ACK code is transmitted.
In this instance, the "ready for reception" state is maintained.
When transmitting printing, print conditions, user pattern characters, and print data recall
●
When transmitting printing, print conditions, user pattern characters, and print data recall, ensure that
the print conditions, user pattern characters, and print data recall are transmitted prior to the printing.
If the printing is transmitted earlier than the other data, the "not ready for reception" state prevails.
Therefore, the subsequent transmission of the print conditions, user registration characters, and print
data recall causes a communication error.
(c) When the "not ready for reception" state prevails after transmission data recep-
tion from the external device
●
The NAK code is transmitted in response to the ENQ code reception from the outside.
(d) Transmission data received from the external device
●
Error-free transmission data is stored in the IJ printer. The same contents are printed until different
transmission data is transmitted to the IJ printer.
●
If the data transmitted from the external device is in error, the IJ printer printings remain unchanged.
In such an instance, retransmit the data beginning as explained in (b).
The retransmission count setup must be determined from the device side.
2
1
3
