Intermec PX6i Fingerprint Developer's Guide (old) - Page 69
Using an ON LINE | OFF LINE Statement, Controlling Printer Response with VERBON | VERBOFF
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Chapter 4 - Managing Input and Output The status of the PE signal can be read by a PRSTAT statement, as in this example: IF (PRSTAT AND 4) GOTO.....ELSE GOTO..... Note: Issuing a READY statement is no guarantee that the printer will receive data. There may be other conditions that hold up the reception, such as a full receive buffer. Using an ON LINE | OFF LINE Statement These two statements are only used for the parallel Centronics communication channel and control the SELECT signal (pin 13 on the parallel interface board). Controlling Printer Response with VERBON | VERBOFF These commands control the printer verbosity, which refers to the printer response (on the standard OUT channel) to instructions received on the standard IN channel: By default, verbosity is on (VERBON) in Fingerprint, but off (VERBOFF) in the Direct Protocol. The verbosity level is controlled by the system variable SYSVAR(18). All responses are suppressed when a VERBOFF statement is issued. However, VERBOFF does not suppress question marks or other prompts displayed as a result of another command, such as an INPUT statement. Instructions like DEVICES, FILES, FONTS, IMAGES, LIST and PRINT also work normally. When the printer receives a character, such as from the host keyboard, the same character is echoed back on the standard OUT channel by default. When an instruction has been checked for syntax errors and accepted, the printer returns "Ok". Otherwise an error message is returned. This example demonstrates how the printer is set to only return "Ok" after correct lines (2) or error messages after failed lines (8): SYSVAR(18) = 10 Managing Background Communication Background communication means that the printer receives data on an IN channel while the program runs in a loop. The data is stored in a buffer that can be emptied at an appropriate moment by the running program, which then uses the data. Background communication buffers are not the same as the receive buffers. Any input received on a communication channel is first stored in the channel receive buffer, awaiting processing. After processing, the data may be stored in the background communication buffer. Intermec Fingerprint Developer's Guide 53