.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later .. c:namespace:: DTV.fe .. _FE_SET_TONE: ***************** ioctl FE_SET_TONE ***************** Name ==== FE_SET_TONE - Sets/resets the generation of the continuous 22kHz tone. Synopsis ======== .. c:macro:: FE_SET_TONE ``int ioctl(int fd, FE_SET_TONE, enum fe_sec_tone_mode tone)`` Arguments ========= ``fd`` File descriptor returned by :c:func:`open()`. ``tone`` an integer enumered value described at :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. Return Value ============ On success 0 is returned. On error -1 is returned, and the ``errno`` variable is set appropriately. Generic error codes are described at the :ref:`Generic Error Codes ` chapter.