Programmer's Guide
PcOS Series 90PLUS
Printer Control Codes
Printer Status Set/Inquire
12/16/99
Rev M
Page 83
PE
DATA
STROBE
BUSY
ACK
Valid
ID
Next
Figure 20 PE to ENQ request timing
5.15.2
Serial Mode Inquire
All inquire commands require a response from the printer. In serial operation, inquire commands are
responded to by an acknowledged (ACK) or not acknowledged (NAK), the command ID, and, in some
cases, status. The serial ACK or NAK responses are always uniform and followed with a command ID.
This makes the design of the host application easier.
The printer will always accept serial data even if the printer is off-line. It is possible to send inquire
commands to the printer even when it is off-line. Because inquire commands are processed before they go
in the buffer, the printer will respond even when it is busy.
In serial mode, it is desirable that the response to an inquire command be received by the host before
another inquire command is issued to the printer. When the printer receives an inquiry, it must generate a
response. If inquiries are sent to the printer too fast, the printer will spend all of its time responding to
them and have no time to print.
5.15.3
Parallel, IEEE 1284 Mode Inquire
In parallel, IEEE 1284 mode, there is a way to return status information to the host. After the host makes
an inquire request, it can activate parallel, IEEE 1284 Mode 0, reverse channel and wait for a response
from the printer. The response to an inquire command is identical to serial mode.
The printer will always accept parallel, IEEE 1284 reverse channel requests but will not accept inquire
commands when it is off-line. It is possible to obtain status when off-line by placing the printer in
dynamic response mode before the printer goes off-line. The IEEE 1284 reverse channel will then respond
to status changes even if the printer is off-line. It is also possible to configure the printer, so it will not go
off-line in most cases. Power off, paper out, and faults will always generate off-line status.
5.15.4
Dynamic Response Mode
Dynamic status, [ESC] w <n>, can be used to allow the host to sense status changes without sending
repeated inquire commands. The operation of the dynamic response varies depending on the configuration
of the printer. If the printer is configured for serial or parallel, IEEE 1284 operation, more than one status
can be sensed as the printer will respond to status changes as if an [ENQ] were issued. In parallel mode,
only one status should be requested. If more than one bit is active, the resulting status on the PE signal
will not be defined.
Summary of Contents for PcOS series 90plus
Page 1: ...P OS c SERIES 90PLUS Receipt Validation Journal Printers PROGRAMMER S GUIDE Rev M PN 100 7586 ...
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Page 6: ...PcOS Series 90PLUS Programmer s Guide Page iv Rev M 12 16 99 ...
Page 139: ...Programmer s Guide PcOS Series 90PLUS Product Self Tests 12 16 99 Rev M Page 127 73 Italian ...
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Page 180: ...INSERT PN 100 7307 Rev M 12 16 99 ...