Intermec CK30

Chapter 4 — Theory of Operation
Pin 1
10-pin Stewart 937-SP-301010R-K2
(View looking into connector)
Tethered Scanner Connector
Tethered Scanner Auto-Detect
The 072786 tethered scan flex assembly incorporates a MAX471 current
sensor (U1) to detect when a tethered scanner is plugged in. This is
intended as a piece of a scanner “Plug and Play” strategy, but is not
implemented in the current software. Comparator U2 compares the
current sensor output to a resistive divider reference, and drives its open-
drain output connected to the IMAGER_PIXCLK FPGA input:
High-Z (float high) = no SCAN_5V current => no scanner installed
0V = ≥ 5mA SCAN_5V current => scanner installed
The TRIG_AIM* signal in this case is used to enable and disable the auto-
detect feature such that when disabled, the current sensor output is high-
Z, so it does not interfere with the IMAGER_PIXCLK signal alternate
scanner function (BEEP).
TRIG_AIM* = 0 => auto-detect enabled
TRIG_AIM* = 1 => auto-detect disabled
Since some scanners draw little or no current until the trigger is pulled, the
auto-detect feature may not function until the scanner trigger is pulled.
The auto-detect signal should be ignored during transitions (most often
occurring on Suspend and Resume) when the current sensor changes state
as SCAN_5V is enabled and disabled, possibly giving a false scanner
detection.
Inverter U3, driven by the SCAN_EN signal, is used to switch the DBP,
SOS and Trigger pull-ups to pull-downs to aid in the scanner auto-ID
process. This is useful for distinguishing newer decoded-output scanners
from older legacy DBP-mode undecoded scanners.
Tethered Scanner Support Through Dock Connector
Decoded-output tethered scanners and undecoded (DBP) tethered
scanners are also supported through 26-pin docking connector J13, mostly
so that a tethered scanner can be left attached to a vehicle dock and
become active when the CK30 is docked.
CK30 Handheld Computer Service Manual 85