From 8e4bff4cab0ddac6060645b0715210484d02ff40 Mon Sep 17 00:00:00 2001
From: Yuval Adam <_@yuv.al>
Date: Wed, 30 Aug 2017 08:25:59 +0000
Subject: Initial file dump from open source release
---
Documentation/DocBook/media/v4l/dev-teletext.xml | 29 ++++++++++++++++++++++++
1 file changed, 29 insertions(+)
create mode 100644 Documentation/DocBook/media/v4l/dev-teletext.xml
(limited to 'Documentation/DocBook/media/v4l/dev-teletext.xml')
diff --git a/Documentation/DocBook/media/v4l/dev-teletext.xml b/Documentation/DocBook/media/v4l/dev-teletext.xml
new file mode 100644
index 00000000..bd21c64d
--- /dev/null
+++ b/Documentation/DocBook/media/v4l/dev-teletext.xml
@@ -0,0 +1,29 @@
+ Teletext Interface
+
+ This interface was aimed at devices receiving and demodulating
+Teletext data [, ], evaluating the
+Teletext packages and storing formatted pages in cache memory. Such
+devices are usually implemented as microcontrollers with serial
+interface (I2C) and could be found on old
+TV cards, dedicated Teletext decoding cards and home-brew devices
+connected to the PC parallel port.
+
+ The Teletext API was designed by Martin Buck. It was defined in
+the kernel header file linux/videotext.h, the
+specification is available from
+ftp://ftp.gwdg.de/pub/linux/misc/videotext/. (Videotext is the name of
+the German public television Teletext service.)
+
+ Eventually the Teletext API was integrated into the V4L API
+with character device file names /dev/vtx0 to
+/dev/vtx31, device major number 81, minor numbers
+192 to 223.
+
+ However, teletext decoders were quickly replaced by more
+generic VBI demodulators and those dedicated teletext decoders no longer exist.
+For many years the vtx devices were still around, even though nobody used
+them. So the decision was made to finally remove support for the Teletext API in
+kernel 2.6.37.
+
+ Modern devices all use the raw or
+sliced VBI API.
--
cgit v1.3.1