Instruction manual

A758 Owner’s Guide Chapter 7: Programming Guide
September 1999 154
Status Commands
Status Command Introduction
The A758 has three methods of providing status to the application. These
methods are through Batch Status Commands, Real Time Status Commands, and
Auto Status Back. An application may use one or more of these methods to
understand the current status of the printer. A brief description of each of these
methods follows.
Batch Status Commands
– These commands are sent to the printer and stored in
the printer’s buffer. Once the printer has processed all the previous commands
these commands are processed and the proper status is returned to the
application. In the event a condition causes the printer to go BUSY, it stops
processing commands from the printer buffer. If a Batch Status Command
remained in the buffer during this busy condition, it would not be processed. In
fact, no Batch Commands are processed while the printer is in this state.
Real-Time Commands
– These commands are sent to the printer and are NOT
stored in the printer’s buffer. Instead, they are acted on immediately (regardless
of the printer’s BUSY status) and their response (if any) is returned to the
application. This gives the application the ability to query the printer when it is in
a busy state in order to correct whatever fault has occurred.
Auto Status Back
– This mechanism allows the application developer to program
the printer to automatically respond with a four byte status when certain
conditions in the printer change.
Please see the subsequent sections for a more detailed description of these status
commands. At the end of this Status Commands section is a page entitled
“Recognizing Data from the Printer”. This describes how to interpret what
command or setting (in the case of Auto Status Back) triggered a response from
the printer.