CognitiveTPG A799 - Manual (Page 82)

Chapter 4: Programming Commands 82 Revision D 12/09
A799-PG00001D
Status
Status command introduction
The A799 has three methods of providing status to the application. These methods are through batch status commands, real
time status commands and unsolicited status mode. 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 buffer. Periodically, when the printer has time, it scans
the input buffer looking for these commands. When found by the printer, these commands are processed immediately. 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.
Unsolicited status mode – 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 unsolicited status mode) triggered a response from the printer.
Batch mode
For RS-232C printers, these commands enable the printer to communicate with the host computer following the selected
handshaking protocol, either DTR/DSR or XON/XOFF. They are stored in the printer’s data buffer as they are received,
and are handled by the firmware in the order in which they are received.
When a fault occurs, the printer will go busy at the
RS-232C interface and not respond to any of the batch mode printer status commands. If the fault causing the busy
condition can be cleared, such as by loading paper, or letting the thermal printhead cool down, the printer will resume
processing the data in its receive buffer.
Transmit peripheral device status (RS-232C printers only)
ASCII ESC u 0
Hexadecimal 1B 75 0
Decimal 27 117 0
Value of returned byte:
Bit 0 Bit 1
1 = Drawer 1 Closed 1 = Drawer 2 Closed
0 = Drawer 1 Open 0 = Drawer 2 Open
Bits 2–7 are not used.
Transmits current status of the cash drawers. One byte is sent to the host computer. In DTR/DSR protocol, the printer waits
for DSR = SPACE. If a drawer is not connected, the status will indicate it is closed.
Exceptions
Unlike the A793, that had a dedicated connector and resultant dedicated status reporting for each cash drawer, the A799 has
a single connector that shares data reporting from either cash drawer. When either cash drawer is open, an open status is
reported by the printer.
Related information
In LEGACY emulation, this command is ignored.