Westermo's short haul modem MD-12 is used for data communication over long distances and in harsh environments. The MD-12 is used to connect equipment with RS-232/V.24 interfaces. Westermo's ±10 mA (W1) balanced current loop transmission technique makes it possible to transmit data up to 18 km at low data rates. At shorter ranges transmission rates up to 38.4 kbit/s can be achieved. All Westermo's modems using the 10 mA current loop (W1) technique are compatible with each other.