Intermec PC43d Fingerprint Developer's Guide (PC23d, PC43d/t, PM23c, PM43, PM4 - Page 63

Using an ON LINE | OFF LINE Statement, Controlling Printer Response with VERBON | VERBOFF

Page 63 highlights

Chapter 4 - Managing Input and Output 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 is first stored in the channel receive buffer, awaiting processing. After processing, you can store the data in the background communication buffer. The following Fingerprint commands are used in connection with background communication: • COMSET sets the background reception parameters, including: • communication channel. • start and end character(s) of message string. • characters to be ignored. • attention string that interrupts reception. • maximum number of characters to be received. • ON COMSET GOSUB branches the program execution to a subroutine when background reception on a specified channel is interrupted. • COMSET ON empties the buffer and turns on background reception on the specified channel. Fingerprint Developer's Guide 51

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
  • 57
  • 58
  • 59
  • 60
  • 61
  • 62
  • 63
  • 64
  • 65
  • 66
  • 67
  • 68
  • 69
  • 70
  • 71
  • 72
  • 73
  • 74
  • 75
  • 76
  • 77
  • 78
  • 79
  • 80
  • 81
  • 82
  • 83
  • 84
  • 85
  • 86
  • 87
  • 88
  • 89
  • 90
  • 91
  • 92
  • 93
  • 94
  • 95
  • 96
  • 97
  • 98
  • 99
  • 100
  • 101
  • 102
  • 103
  • 104
  • 105
  • 106
  • 107
  • 108
  • 109
  • 110
  • 111
  • 112
  • 113
  • 114
  • 115
  • 116
  • 117
  • 118
  • 119
  • 120
  • 121
  • 122
  • 123
  • 124
  • 125
  • 126
  • 127
  • 128
  • 129
  • 130
  • 131
  • 132
  • 133
  • 134
  • 135
  • 136
  • 137
  • 138
  • 139
  • 140
  • 141
  • 142
  • 143
  • 144
  • 145
  • 146
  • 147
  • 148
  • 149
  • 150
  • 151
  • 152
  • 153
  • 154
  • 155
  • 156
  • 157
  • 158
  • 159
  • 160
  • 161
  • 162
  • 163

Chapter 4 — Managing Input and Output
Fingerprint Developer’s Guide
51
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 is first stored in the channel receive buffer, awaiting processing. After
processing, you can store the data in the background communication buffer.
The following Fingerprint commands are used in connection with background
communication:
COMSET sets the background reception parameters, including:
communication channel.
start and end character(s) of message string.
characters to be ignored.
attention string that interrupts reception.
maximum number of characters to be received.
ON COMSET GOSUB branches the program execution to a subroutine when
background reception on a specified channel is interrupted.
COMSET ON empties the buffer and turns on background reception on the
specified channel.