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56 lines
1.4 KiB
56 lines
1.4 KiB
.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later |
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.. c:namespace:: DTV.fe |
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.. _FE_SET_TONE: |
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***************** |
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ioctl FE_SET_TONE |
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***************** |
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Name |
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==== |
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FE_SET_TONE - Sets/resets the generation of the continuous 22kHz tone. |
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Synopsis |
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======== |
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.. c:macro:: FE_SET_TONE |
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``int ioctl(int fd, FE_SET_TONE, enum fe_sec_tone_mode tone)`` |
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Arguments |
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========= |
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``fd`` |
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File descriptor returned by :c:func:`open()`. |
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``tone`` |
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an integer enumered value described at :c:type:`fe_sec_tone_mode` |
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Description |
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=========== |
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This ioctl is used to set the generation of the continuous 22kHz tone. |
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This call requires read/write permissions. |
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Usually, satellite antenna subsystems require that the digital TV device |
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to send a 22kHz tone in order to select between high/low band on some |
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dual-band LNBf. It is also used to send signals to DiSEqC equipment, but |
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this is done using the DiSEqC ioctls. |
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.. attention:: If more than one device is connected to the same antenna, |
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setting a tone may interfere on other devices, as they may lose the |
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capability of selecting the band. So, it is recommended that applications |
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would change to SEC_TONE_OFF when the device is not used. |
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Return Value |
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============ |
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On success 0 is returned. |
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On error -1 is returned, and the ``errno`` variable is set |
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appropriately. |
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Generic error codes are described at the |
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:ref:`Generic Error Codes <gen-errors>` chapter.
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