PSC Scanners - Manual (Page 39)

06656 33
Power Standby and Serial Commands
When the scanner is programmed for standby power operation (@B),
the first character of the command is used to “wake-up” the scanner;
it is not properly received by the scanner’s CPU. Therefore, when
there is any possibility that the scanner is in standby mode, an extra
space code should be transmitted before STX to ensure the scanner is
“awake” before sending commands to it. If the scanner is not being
operated in standby mode, the space has no effect on commands
(space prefixed commands are properly decoded). Having sent the
space code to “wake-up” the scanner, a 150 to 200 millisecond pause
must be observed to allow the scanner’s CPU to complete its initial-
ization tasks, during which time it is unable to accept serial com-
mands before issuing the programming command. Failure to observe
this delay causes the scanner to ignore the incoming command.
Communication Parameter Changes
All commands which affect serial communication are acted upon
immediately. Therefore, when changing communication parameters
(baud rate, word length, parity, etc.), the scanner will send the ACK
Code, using the newly implemented communication parameters.
There should be enough of a delay from the issuance of a communi-
cation parameter setup command for the properly programmed host
computer to modify its internal parameters and correctly receive the
ACK code sent by the scanner. This is due to the internal, one second
delay required for the scanner to update its internal EEPROM.
Manual Scanning Interaction
The decoder firmware makes no attempt to resolve conflicts between
serial programming commands and manually scanned menu labels.
If you plan to scan menu labels from the PSC Operator’s Manual, do
not attempt serial programming, and vice versa. Serial commands are
given priority over pending menu labels. For example, if you scan the
menu label SET I 2 of 5 MINIMUM LENGTH and the scanner is wait-
ing for a two-digit, minimum length code when a serial command is
issued, the serial command is acted upon and the pending manual
command SET I 2 of 5 MINIMUM LENGTH is ignored.