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Revision as of 05:33, 14 November 2003 by Richardpitt (talk | contribs)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)Back Channel in a telecommunications system typically is a low-speed or less-than-optimal transmission channel opposite to the main channel's direction. The system is asymmetric in that the communication is not the same speed or capacity in both directions - the back-channel being the subservient or lower speed/capacity direction.
In many cases the back-channel is used mostly for acknowlegements of the validity of the forward-channel's data (i.e. that the forward-channel's data passes validity tests of some sort.)
Examples
ADSL where the "A" stands for "asymmetric" and the channel from the subsciber to the supplier is slower/less capacity than the channel from the supplier (ISP) to the subscriber - the channel from the subscriber to the supplier is the back-channel.