OM1 to OM4 fiber optic cables can only transmit wavelengths of 850 nanometers. As a result, data can only flow in one direction. Therefore, at least two fibers are always required: one for sending and one for receiving. This applies to data rates of up to ten gigabits per second. At higher data rates, such as 40 to 100 gigabits, the data streams are divided into packets of ten during transmission and reassembled at the receiver. The technical term for this is "parallel optical transmission." Thus, for the transmission of 40 gigabits, four fibers are needed for sending and an equal number for receiving, totaling eight fibers. For 100 gigabits, 20 fibers are used accordingly. An OM5 cable combines the techniques of Short Wave Division Multiplexing (SWDM) and Wideband Multimode Fiber (WBMMF). Older multimode fibers are optimized for the wavelength range of 850 nanometers. Using SWDM technology, wavelengths can be utilized.