Physical Optics Corp. has announced its 6542 two-channel optical multiplexer-demultiplexer transmission system for fiber optic data networks. Each channel supports up to a 180-Mb/s data rate with an aggregate bandwidth of up to 360 Mb/s per fiber per direction without reducing distance. The 6542 features data multiplexing, and single- and multimode fiber conversion or wavelength conversion in a single box. The company says it is an affordable means for extending network distance and expanding network capacity. A four-channel model, the 6544, also is available.