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.. -*- coding: utf-8; mode: rst -*-
.. _FE_SET_TONE:
*****************
ioctl FE_SET_TONE
*****************
Name
====
FE_SET_TONE - Sets/resets the generation of the continuous 22kHz tone.
Synopsis
========
.. c:function:: int ioctl( int fd, FE_SET_TONE, enum fe_sec_tone_mode *tone )
:name: FE_SET_TONE
Arguments
=========
``fd``
File descriptor returned by :ref:`open() <frontend_f_open>`.
``tone``
pointer to enum :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.
.. c:type:: fe_sec_tone_mode
.. flat-table:: enum fe_sec_tone_mode
:header-rows: 1
:stub-columns: 0
- .. row 1
- ID
- Description
- .. row 2
- .. _SEC-TONE-ON:
``SEC_TONE_ON``
- Sends a 22kHz tone burst to the antenna
- .. row 3
- .. _SEC-TONE-OFF:
``SEC_TONE_OFF``
- Don't send a 22kHz tone to the antenna (except if the
FE_DISEQC_* ioctls are called)
Return Value
============
On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately. The generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.
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