Documentation/media/uapi/dvb/fe-set-tone.rst

   1 .. -*- coding: utf-8; mode: rst -*-
   2
   3 .. _FE_SET_TONE:
   4
   5 *****************
   6 ioctl FE_SET_TONE
   7 *****************
   8
   9 Name
  10 ====
  11
  12 FE_SET_TONE - Sets/resets the generation of the continuous 22kHz tone.
  13
  14
  15 Synopsis
  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
  22 Arguments
  23 =========
  24
  25 ``fd``
  26     File descriptor returned by :ref:`open() <frontend_f_open>`.
  27
  28 ``tone``
  29     pointer to enum :c:type:`fe_sec_tone_mode`
  30
  31
  32 Description
  33 ===========
  34
  35 This ioctl is used to set the generation of the continuous 22kHz tone.
  36 This call requires read/write permissions.
  37
  38 Usually, satellite antenna subsystems require that the digital TV device
  39 to send a 22kHz tone in order to select between high/low band on some
  40 dual-band LNBf. It is also used to send signals to DiSEqC equipment, but
  41 this 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 .. c:type:: fe_sec_tone_mode
  49
  50 .. flat-table:: enum fe_sec_tone_mode
  51     :header-rows:  1
  52     :stub-columns: 0
  53
  54
  55     -  .. row 1
  56
  57        -  ID
  58
  59        -  Description
  60
  61     -  .. row 2
  62
  63        -  .. _SEC-TONE-ON:
  64
  65           ``SEC_TONE_ON``
  66
  67        -  Sends a 22kHz tone burst to the antenna
  68
  69     -  .. row 3
  70
  71        -  .. _SEC-TONE-OFF:
  72
  73           ``SEC_TONE_OFF``
  74
  75        -  Don't send a 22kHz tone to the antenna (except if the
  76           FE_DISEQC_* ioctls are called)
  77
  78
  79 Return Value
  80 ============
  81
  82 On success 0 is returned, on error -1 and the ``errno`` variable is set
  83 appropriately. The generic error codes are described at the
  84 :ref:`Generic Error Codes <gen-errors>` chapter.