World Library  
Flag as Inappropriate
Email this Article

Return channel

Article Id: WHEBN0002621372
Reproduction Date:

Title: Return channel  
Author: World Heritage Encyclopedia
Language: English
Subject: Backchannel (disambiguation), Point-to-multipoint communication, The lexer hack, Backward channel, Upstream (networking)
Collection: Communication Circuits
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Return channel

In communications systems, the return channel (also reverse channel or return link) is the transmission link from a user terminal to the central hub.

Return links are often, but not always, slower than the corresponding forward links. Examples where this is true include asymmetric digital subscriber line, cable modems, mobile broadband and satellite internet access.

The return channel need not use the same medium as the main channel. For example, some hybrid Internet access services use a one-way cable television system for the forward channel and a dial-up modem for the return channel.

Even when the return and forward channels use the same medium, their differences often dictate the use of very different data modulation and coding techniques. For example, in a star radio network, only the central hub transmits on the forward link, so channel access method is a consideration only on the return link.

The "forward/return" terminology is also used for spacecraft command and telemetry links. Because the return link carries telemetry, often including imagery, it is often orders of magnitude faster than the forward link that transmits only a few predefined spacecraft commands.

Return and forward channels are distinct from, and should not be confused with, uplinks and downlinks in satellite communication systems. For example, satellite internet access with conventional bent-pipe transponders require a total of two uplinks and two downlinks. One uplink and downlink pair are used for the forward link from the central ground hub through the satellite to the user terminal, and another uplink/downlink pair are used for the return link from the user terminal to the central hub.

See also


This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.