Tyco Electronics LD9000 Series - Manual (Page 33)

2) Now scan the barcode below to change your scanning pattern. Using this
scanning pattern will allow you to read 2-D barcodes (you can still read 1-D
barcodes also).
The scanner module also adds a Hall Effect Switch (HE Switch) that enables the unit to
automatically set the Trigger mode of the Scan Engine depending on the location of an
external magnet (included in scanner cradle).
The output of the HE Switch switches low (turns ON) when a magnetic field (south
polarity) perpendicular to the Hall sensor exceeds the operate point threshold, B
OP
(typically 100 G magnetic field). When the magnetic field is reduced below the release
point, B
RP
, (typically 45 G magnetic field) the HE Switch output goes high (turns OFF).
The Hall Effect Switch goes to the USB Controller’s DSR input. As the HE Switch
opens or closes, it causes the USB Controller to initiate a USB Interrupt message to the
host. When the Host Application software detects the DSR input active LOW via the
USB Interrupt and a CDC message (HE Switch is ON), it sends a ‘Continuous Trigger’
SSI command to the Symbol Scan Engine.
The Scan Engine turns on the laser and is able to scan and decode barcodes continuously
without the user having to press the trigger (momentary switch). When the Host Appli-
cation software detects the DSR input HIGH (HE Switch is OFF), it sends a ‘Level
Trigger’ SSI command to the Symbol Scan Engine. The Scan Engine turns off the laser
and will scan and decode barcodes only when the trigger is activated.
2-28 Elo Touchmonitor User Guide