Data Communications Networking Devices - 4th Ed.pdf

680 _________________________ WIDE AREA NETWORK DATA CONCENTRATION EQUIPMENTFigure 6.36 Inverse multiplexer operation.An inverse multiplexer splits a transmitted datastream into odd and even bits which are transmitted over two voice-grade circuits andrecombined at the distant endFigure 6.37 Inverse multiplexing using satellite±terrestrial circuits.One type of `plexing'con®guration could involve the use of a satellite link for one data stream with a ground orundersea cable link for the otherdifference in transmission delays the bit stream could not be reassembled correctly.In this type of application, the failure of one circuit can be compensated bytransmitting the entire data load over the remaining channel at one-half the normalrate.Typical applicationsAs stated previously, one key advantage obtained by using inverse multiplexers isthe cost savings associated with using a few multiple low-speed lines in place of asingle higher operating rate transmission facility. Another advantage afforded bythese devices gives the user the ability to con®gure and recon®gure their networkbased upon the range of distinct speeds available to meet changing requirements.For example, consider the use of four 33.6 kbps speed-selectable modems used witha pair of inverse multiplexers. You could use this hardware con®guration with two