1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 2 .. c:namespace:: DTV.fe 3 4 .. _FE_SET_TONE: 5 6 ***************** 7 ioctl FE_SET_TONE 8 ***************** 9 10 Name 11 ==== 12 13 FE_SET_TONE - Sets/resets the generation of the continuous 22kHz tone. 14 15 Synopsis 16 ======== 17 18 .. c:macro:: FE_SET_TONE 19 20 ``int ioctl(int fd, FE_SET_TONE, enum fe_sec_tone_mode tone)`` 21 22 Arguments 23 ========= 24 25 ``fd`` 26 File descriptor returned by :c:func:`open()`. 27 28 ``tone`` 29 an integer enumered value described at :c:type:`fe_sec_tone_mode` 30 31 Description 32 =========== 33 34 This ioctl is used to set the generation of the continuous 22kHz tone. 35 This call requires read/write permissions. 36 37 Usually, satellite antenna subsystems require that the digital TV device 38 to send a 22kHz tone in order to select between high/low band on some 39 dual-band LNBf. It is also used to send signals to DiSEqC equipment, but 40 this is done using the DiSEqC ioctls. 41 42 .. attention:: If more than one device is connected to the same antenna, 43 setting a tone may interfere on other devices, as they may lose the 44 capability of selecting the band. So, it is recommended that applications 45 would change to SEC_TONE_OFF when the device is not used. 46 47 Return Value 48 ============ 49 50 On success 0 is returned. 51 52 On error -1 is returned, and the ``errno`` variable is set 53 appropriately. 54 55 Generic error codes are described at the 56 :ref:`Generic Error Codes <gen-errors>` chapter.
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