Hitachi PH - Communication Timing

● Communication Timing 6-41
6.5 Communication Timing
6.5.1 Signal Timing
6.5.1-1 In overwrite-protected mode
Off-line
On-line
External
device
IJ printer
ENQ
NAK
STX
ETX
ACK
(No signal output)
Readiness
for reception
Print start signal
Printing
operation
Ready for
reception
Not ready for
reception
(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 Online/Offline key 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 with the ENQ code.
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 main-
tained.
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.
1
2
3
ENQ
ACK
STX
ETX
ENQ
ENQ ENQ
STX
ETX
ACK
ACK
ACK
ACKNAK
AB
C
C
(a)
(b) (c) (c)
AB
C