1.. -*- coding: utf-8; mode: rst -*-
2
3.. _FE_SET_TONE:
4
5*****************
6ioctl FE_SET_TONE
7*****************
8
9Name
10====
11
12FE_SET_TONE - Sets/resets the generation of the continuous 22kHz tone.
13
14
15Synopsis
16========
17
18.. c:function:: int ioctl( int fd, FE_SET_TONE, enum fe_sec_tone_mode tone )
19    :name: FE_SET_TONE
20
21
22Arguments
23=========
24
25``fd``
26    File descriptor returned by :ref:`open() <frontend_f_open>`.
27
28``tone``
29    an integer enumered value described at :c:type:`fe_sec_tone_mode`
30
31
32Description
33===========
34
35This ioctl is used to set the generation of the continuous 22kHz tone.
36This call requires read/write permissions.
37
38Usually, satellite antenna subsystems require that the digital TV device
39to send a 22kHz tone in order to select between high/low band on some
40dual-band LNBf. It is also used to send signals to DiSEqC equipment, but
41this is done using the DiSEqC ioctls.
42
43.. attention:: If more than one device is connected to the same antenna,
44   setting a tone may interfere on other devices, as they may lose the
45   capability of selecting the band. So, it is recommended that applications
46   would change to SEC_TONE_OFF when the device is not used.
47
48
49Return Value
50============
51
52On success 0 is returned.
53
54On error -1 is returned, and the ``errno`` variable is set
55appropriately.
56
57Generic error codes are described at the
58:ref:`Generic Error Codes <gen-errors>` chapter.
59