Wireless data modems
Now available in module form, wireless data modems can be equipped with three variations of wireless technology. The family of modules share similar operating characteristics in the 2.4-GHz-ISM band under FCC Part 15.247. All three devices can support various network configurations and include an asynchronous, serial 3V-CMOS level interface for ease of connection to an embedded host or an RS-232 type driver. The FRH-07T version features high performance with low current consumption of less than 35mA for transmitting and receiving operations, and less than 70uA for‘sleep’ mode operations. The data rate is programmable from 300 bps to 115.2 kbps. Single frequencies or groupings are selectable from an available 94, and operating distance is 1,000 ft LOS with a transmission power of less than 5 mW/MHz due to signal-to-noise ratio. Automatic error detection and retransmission are included in the firmware. A diversity antenna feature with two ports helps overcome reception problems in areas prone to multipath fading commonly encountered in manufacturing plants. The FDL-01 also features high performance with a higher data rate of 300 bps to 230.4 kbps, trading off higher current consumption of less than 110 mA for transmitting and receiving operations, and less than 1 mA for ‘sleep’ mode operation. The FDP01T provides a smaller, lower cost solution. Its footprint is 25 x 33 mm, allowing it to mount easily to a PCB. With a height of only3 mm, it can fit into compact, portable designs. Lower cost is achieved by using FSK modulation in 80 frequencies and lower transmitting power.