The LPI is the first current loop (4-to-20 and 10-to-50-mA) powered wireless (RF) transceiver, according to the manufacturer.
It draws power from the current loop and when not transmitting, stores energy in a capacitor. A controller adjusts transmission frequency and an LED indicates if there is a loop signal. The companion receiver converts RF back into a 4-to-20-mA signal while LEDs indicate reception quality. It can be DIN-rail mounted or connected in line (two wires) next to other loop-powered meters. It is available in the following frequencies (depending on the country to be used): 315, 413, 902-928, and 868 MHz (an affidavit of use is required for all frequencies except 902-928 MHz).
Otek Corp., 4016 E. Tennessee St., Tucson, AZ 85714, (877) 227-6835, otekcorp.com