Wincor Nixdorf TH250, Programmer'S Manual

Page: 83 / 182

TH250 Programmer’s Guide
78
Status
Status command introduction
The TH250 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.
Automatic status back or 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