Editing Transparency (telecommunication)

{{Use dmy dates|date=October 2023}}
{{Short description|Property of a telecommunication system that allows data to pass through unchanged}}

In [[telecommunications]], '''''transparency''''' can refer to: 
#The property of an entity that allows another entity to pass through it without altering either of the entities. 
#The property that allows a [[transmission system]] or [[channel (communications)|channel]] to accept, at its input, unmodified [[user information]], and deliver corresponding user information at its [[Output (computing)|output]], unchanged in form or information content. The user information may be changed internally within the transmission system, but it is restored to its original form prior to the output without the involvement of the user.
#The quality of a [[data]] [[communications system]] or device that uses a [[bit]]-oriented [[link protocol]] that does not depend on the bit [[sequence]] structure used by the data source.<ref>{{FS1037C MS188}}</ref><ref>{{DODDIC}}</ref>

Some communication systems are not transparent.
Non-transparent communication systems have one or both of the following problems:
* user data may be incorrectly interpreted as internal commands. For example, modems with a [[Time Independent Escape Sequence]] or 20th century [[Signaling System No. 5]] and [[R2 signalling]] telephone systems, which occasionally incorrectly interpreted user data (from a "[[blue box (phreaking)|blue box]]") as commands.
* output "user data" may not always be the same as input user data. For example, many early [[email]] systems were not [[8-bit clean]]; they seemed to transfer typical short text messages properly, but converted "unusual" characters (the [[control character]]s, the "[[high ASCII]]" characters) in an irreversible way into some other "usual" character. Many of these systems also changed user data in other irreversible ways &ndash; such as inserting [[linefeed]]s to make sure each line is less than some maximum length, and inserting a ">" at the beginning of every line that begins with "From ".<ref>{{cite web | url=http://www.jwz.org/doc/content-length.html | title=Configuring Netscape Mail on Unix: Solaris and Content-Length | access-date=9 April 2009 | archive-date=8 April 2009 | archive-url=https://web.archive.org/web/20090408050212/http://www.jwz.org/doc/content-length.html | url-status=live }}</ref> Until [[8BITMIME]], a variety of [[binary-to-text encoding]] techniques have been overlaid on top of such systems to restore transparency &ndash; to make sure that any possible file can be transferred so that the final output "user data" is actually identical to the original user data.

== References ==
{{reflist}}

== See also ==
* [[In-band signaling]]
* [[Out-of-band data|out-of-band]] communication

[[Category:Telecommunications engineering]]