Wincor Nixdorf TH320, Руководство программиста

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TH320/TH420 Programmers Guide
63
Status Command
The TH320/420 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 and stored in 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.
Batch mode
For RS-232c printers, these commands enable the printer to communicate with the host computer following
the selected handshaking protocol 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 print head cool down, the printer will resume processing the data in
its receive buffer.
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.
Transmit peripheral device status
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.
Transmit 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 A756, that had a dedicated connector and resultant dedicated status reporting for each cash
drawer, the TH320 has a single connector that shares data reporting from either cash drawer. When either
cash drawer is open, an open status for both drawers is reported by the printer.