The devices can communicate at distances in excess of 500m (when using suitable antennas), with the transmitter sporting an output power of +10dBm (10mW), and the receiver possessing a sensitivity of -120dBm (for 12dB SINAD). The transmitter/receiver pair can be set to operate at any frequency within the 433MHz ISM band (though other frequency variants are available, including the UK 458MHz band). Both of these devices are run from a 3.1 – 15V supply, the transmitter consuming a current of 34mA and its partner needing 20mA. The maximum data bit rate is 5kbp/s for standard versions (a quasi-DC data recovery circuit improves performance with unbalanced, asynchronous data streams).
The LMT2 and LMR2 are fully re-programmable via their RS232 interfaces, a total of 32 discrete channels being programmed into the unit (16 of which can be selected via a parallel port). These modules are capable of targeting a broad spectrum of tasks; including handheld terminals, environmental monitoring equipment, barcode scanners, data loggers, vehicle data up/download, industrial telemetry and telecommand, as well as high-end security alarm systems. The LMT2 occupies a 33mm x 23mm x 9mm fully-screened package, while its counterpart takes up 45mm x 23mm x 9mm. The two units have compatible pin-outs, allowing a common board lay-out to accommodate either of them. These radios are designed to conform fully with both EN 300 220-3 and the EN 301 489-3 EMC standards.
