fe-set-tone.rst (1406B)
1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 2.. c:namespace:: DTV.fe 3 4.. _FE_SET_TONE: 5 6***************** 7ioctl FE_SET_TONE 8***************** 9 10Name 11==== 12 13FE_SET_TONE - Sets/resets the generation of the continuous 22kHz tone. 14 15Synopsis 16======== 17 18.. c:macro:: FE_SET_TONE 19 20``int ioctl(int fd, FE_SET_TONE, enum fe_sec_tone_mode tone)`` 21 22Arguments 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 31Description 32=========== 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 device 38to send a 22kHz tone in order to select between high/low band on some 39dual-band LNBf. It is also used to send signals to DiSEqC equipment, but 40this 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 47Return Value 48============ 49 50On success 0 is returned. 51 52On error -1 is returned, and the ``errno`` variable is set 53appropriately. 54 55Generic error codes are described at the 56:ref:`Generic Error Codes <gen-errors>` chapter.