The Comnet FDX55 series consists of fully digital transceiver units designed for implementing simplex or full-duplex RS232 drop-and-repeat poll-and-respond traffic signalization and communications networks over one or two optical fibers. These environmentally hardened units are ideal for unconditioned out-of-plant or roadside installations. 232/422 Drop-and-Repeat Transceiver for singlemode fiber. Supports 1 in/1 out RS232/422 channel over 9/125µm singlemode fiber at 1310/1550 nm. Provides a 23 dB optical budget with distances up to 69 km (43 miles).