Asynchronous Terminals and Printer Processes Programming Manual

PRINTER PROGRAMMING CONSIDERATIONS
DELAYTIME SYSGEN Modifier
Once the I/O process is prevented from sending data to the |
printer, the data flow from the I/O process to the printer is |
halted. However, during this time, the I/O process polls the |
printer for status every 250 milliseconds for n amount of time. |
For example, if DELAYTIME is defined 7500, the I/O process polls |
the printer 300 times. If the printer should return a ready |
status when polled, the I/O process resumes sending data. If |
the printer does not return a ready status when polled during |
the defined time, the I/O process is halted. Consequently, the |
application program is also halted and must be restarted. |
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The DELAYTIME modifier cannot be altered through CMI/CMP. |
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Overprinting |
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The 5515/5516 printers handle overprinting in one of two ways, |
depending on transparency. If you set no transparency by issuing |
SETMODE 6,0,0, the printer appends a carriage return to the |
buffer and only the last two writes are saved for the line before |
issuing a line feed. If you set transparency by issuing SETMODE |
6,0,1, no form control characters are appended to the buffer. |
You must embed form control characters in the data stream to |
accomplish overprinting. |
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CONTROLBUF Limitations |
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These printers do not support CONTROLBUF operations. |
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Resetting the 5515/5516 Printers |
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Resetting the printer ensures that the I/O process and the |
printer are at a known default state. The I/O process performs |
a RESET only once for a device, when the device is first |
opened. The I/O process does not perform another RESET even if |
multiple opens exist on the device. In addition, the I/O process |
can perform a RESET only for operations not controlled by the |
spooler. For operations controlled by the spooler, the spooler |
issues a SETMODE 28 at the beginning of each job. |
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The RESET or SETMODE 28 sets all the SETMODE parameters to their |
SYSGEN values and causes the driver to issue ESC E to the printer. |
The ESC E resets the printer to the front panel defaults, the VFC |
table to its default, and causes a conditional physical top of |
form. |
November 1987 7-27