| .. -*- coding: utf-8; mode: rst -*- | |
| .. _FE_SET_TONE: | |
| ***************** | |
| ioctl FE_SET_TONE | |
| ***************** | |
| Name | |
| ==== | |
| FE_SET_TONE - Sets/resets the generation of the continuous 22kHz tone. | |
| Synopsis | |
| ======== | |
| .. c:function:: int ioctl( int fd, FE_SET_TONE, enum fe_sec_tone_mode tone ) | |
| :name: FE_SET_TONE | |
| Arguments | |
| ========= | |
| ``fd`` | |
| File descriptor returned by :ref:`open() <frontend_f_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. |