| .. 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 <gen-errors>` chapter. |
