Editing Fax (section)

==Related standards==
* T.4 is the umbrella specification for fax.  It specifies the standard image sizes, two forms of image-data compression (encoding), the image-data format, and references, T.30 and the various modem standards.
* T.6 specifies a compression scheme that reduces the time required to transmit an image by roughly 50-percent.
* T.30 specifies the procedures that a sending and receiving terminal use to set up a fax call, determine the image size, encoding, and transfer speed, the demarcation between pages, and the termination of the call.  T.30 also references the various modem standards.
* [[ITU-T V.21|V.21]], [[ITU-T V.27ter|V.27ter]], [[ITU-T V.29|V.29]], [[ITU-T V.17|V.17]], [[ITU-T V.34|V.34]]: ITU modem standards used in facsimile.  The first three were ratified prior to 1980, and were specified in the original T.4 and T.30 standards.  V.34 was published for fax in 1994.<ref>{{cite web| url=http://www.itwissen.info/definition/lexikon/V-34-V-34.html |title=V.34| website=www.itwissen.info|access-date=2018-01-12| archive-url=https://web.archive.org/web/20161228020937/http://www.itwissen.info/definition/lexikon/V-34-V-34.html| archive-date=2016-12-28|url-status=dead}}</ref>
* [[T.37 (ITU-T recommendation)|T.37]] The ITU standard for sending a fax-image file via e-mail to the intended recipient of a fax.
* [[T.38]] The ITU standard for sending Fax over IP (FoIP).
* [[G.711]] pass through - this is where the T.30 fax call is carried in a VoIP call encoded as audio. This is sensitive to network [[packet loss]], [[jitter]] and clock synchronization. When using voice high-compression encoding techniques such as, but not limited to, [[G.729]], some fax tonal signals may not be correctly transported across the packet network.
* {{IETF RFC|3362|link=no}} image/t38 MIME-type
*[https://hylafax.sourceforge.io/sslfax.php SSL Fax] An emerging standard that allows a telephone based fax session to negotiate a fax transfer over the internet, but only if both sides support the standard.  The standard is partially based on T.30 and is being developed by Hylafax+ developers.