TransAct Ithaca 280, Руководство программиста

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Communications iTherm
®
280 Programmer’s Guide
Page 288 Rev K
Display Pass Through
The display pass through feature allows a pole display to be interconnected with the
printer. The printer is connected to a host system with a special serial cable. The host
sends serial data to the printer and the printer sends serial data to the pole display. The
printer does not provide power to the display. During normal printer operation, no data is
passed to the display. In pass through mode, all received data is passed on to the
display.
The restrictions and considerations for pass through are:
1. Pass through only works on serial printers with DTR flow control.
2. XON/XOFF mode does not work correctly.
3. All inquire ([ENQ]) commands are active when not in actual pass through mode.
If, for example, an [ENQ] command for cash drawer status is received by the
printer, the response is transmitted. When pass through is active, all data except
the [ENQ] is passed. The printer does not look for or act on any commands
other than inquires.
4. If pass through data is sent to the printer in continuous mode (i.e. as fast as
possible), each [ENQ] character in the sequence delays the transmit data by one
byte. The printer buffer size is limited. If the buffer overruns, data will be lost.
5. Modem handshake signals from the printer are not controlled during past
through. Their state is set by printer status. Opening the cover toggles the
control lines. When the printer cover is open, it accepts data, including all [ENQ]
commands. If an [ENQ] # is received when off-line, pass through is entered.
6. Previously buffered data is processed by the printer in pass through mode.
Printer performance is degraded by the processing of pass through data.
7. In 8-bit, no parity mode, data is passed through unaltered. In all other modes,
the parity is checked, stripped, and then regenerated by the printer.
8. Pass through has no affect on a printer in parallel mode.
Remote Power Control
The iTherm
®
280 Printer has a remote power control command that instructs it to enter
OFF. When the command is issued, the printer performs print cartridge maintenance
and enters OFF. Unlike pushing the
*
button, remote power mode leaves the
communications active. All commands except the exit power down command are
ignored.
[ESC] y Remote Power Control
ASCII [ESC] y <n>
Hexadecimal 1BH 79H <n>
Decimal <27> <121> <n>
IPCL &%YX17 or &%YX18
EPOS [ESC] y <n>
Where n 17 Requests the printer to enter remote OFF
18 Requests the printer to exit remote OFF