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+.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+.. c:namespace:: DTV.fe
+
+.. _FE_SET_TONE:
+
+*****************
+ioctl FE_SET_TONE
+*****************
+
+Name
+====
+
+FE_SET_TONE - Sets/resets the generation of the continuous 22kHz tone.
+
+Synopsis
+========
+
+.. c:macro:: FE_SET_TONE
+
+``int ioctl(int fd, FE_SET_TONE, enum fe_sec_tone_mode tone)``
+
+Arguments
+=========
+
+``fd``
+    File descriptor returned by :c:func:`open()`.
+
+``tone``
+    an integer enumered value described at :c:type:`fe_sec_tone_mode`
+
+Description
+===========
+
+This ioctl is used to set the generation of the continuous 22kHz tone.
+This call requires read/write permissions.
+
+Usually, satellite antenna subsystems require that the digital TV device
+to send a 22kHz tone in order to select between high/low band on some
+dual-band LNBf. It is also used to send signals to DiSEqC equipment, but
+this is done using the DiSEqC ioctls.
+
+.. attention:: If more than one device is connected to the same antenna,
+   setting a tone may interfere on other devices, as they may lose the
+   capability of selecting the band. So, it is recommended that applications
+   would change to SEC_TONE_OFF when the device is not used.
+
+Return Value
+============
+
+On success 0 is returned.
+
+On error -1 is returned, and the ``errno`` variable is set
+appropriately.
+
+Generic error codes are described at the
+:ref:`Generic Error Codes <gen-errors>` chapter.