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1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later2.. c:namespace:: DTV.fe3 4.. _FE_SET_TONE:5 6*****************7ioctl FE_SET_TONE8*****************9 10Name11====12 13FE_SET_TONE - Sets/resets the generation of the continuous 22kHz tone.14 15Synopsis16========17 18.. c:macro:: FE_SET_TONE19 20``int ioctl(int fd, FE_SET_TONE, enum fe_sec_tone_mode tone)``21 22Arguments23=========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 31Description32===========33 34This ioctl is used to set the generation of the continuous 22kHz tone.35This call requires read/write permissions.36 37Usually, satellite antenna subsystems require that the digital TV device38to send a 22kHz tone in order to select between high/low band on some39dual-band LNBf. It is also used to send signals to DiSEqC equipment, but40this 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 the44 capability of selecting the band. So, it is recommended that applications45 would change to SEC_TONE_OFF when the device is not used.46 47Return Value48============49 50On success 0 is returned.51 52On error -1 is returned, and the ``errno`` variable is set53appropriately.54 55Generic error codes are described at the56:ref:`Generic Error Codes <gen-errors>` chapter.57