User's Manual
ADM Technical Description RFID-LSCAN
File: ADM UserMan.doc Page 10 of 12
Status: Rev1 Last Update: 9/21/2010 3:49:00 PM
3.2 UHF Receiver
The UHF receiver is a narrowband FSK receiver operating in the 433.92 MHz frequency band.
3.2.1 Receive Distance
Table 2 – UHF Receive Distance
Value
Conditions
Min Typ. Max
No obstacles, any tag orientation 10m
3.2.2 Tag message filtration
Only the first read of a tag in a TCP is stored (“tag registration”). However, the ADM can be
programmed to also store the last read of a tag in a TCP (i.e. last time the tag was read prior to be
removed from the mail box). In the event a tag is removed before the second read cycle in a TCP,
the two registrations are identical. This feature is not applicable in continuous mode.
Tag registrations are collected in a non-volatile buffer (“tag buffer”). The tag buffer can store up to
60 registrations. After the capacity of the tag buffer is reached, new registrations are ignored.
3.3 GSM Modem
The ADM communicates with the server (backend) over the GSM network using SMS. It sends
data and unit status information and receives configuration commands and parameters. The
operating frequencies in GSM, DCS and PCS modes are conform to the GSM specifications. The
GSM modem uses an 880~960MHz, 1710~1990 MHz, 0dB Gain integrated antenna.
The GSM modem supports phase 2 GSM11.14 – SIM 1.8V and 3V. The SIM card reader allows
for hot removal of the SIM.
3.4 Test Tag
The ADM integrates a test tag used to monitor unit’s health. The test tag consists of a low power
UHF transmitter, a LF (125kHz) receiver and a microcontroller. The test tag is powered on once a
day. After that, it receives the ADM LF field. Once excited, the test tag transmits a burst of 40
identical messages pseudo-randomly spaced in time. These messages are received by ADM’s
434 MHz receiver and processed like any other messages. Their presence confirms that the ADM
is functioning properly even if no other messages from other tags are registered.
3.5 USB Ports
The ADM has two USB ports: a host port and a slave port. The USB ports are not accessible in
normal operation. One has to remove the battery pack in order to have access to the two ports.
The two ports are only for debug and service and should not be used by the end user.
3.6 LEDs
The main unit is equipped with three LEDs: Power, Busy and GSM. They are normally off and are
only activated for 20 seconds each time when the battery pack is inserted or removed.