85 строки
1.8 KiB
ReStructuredText
85 строки
1.8 KiB
ReStructuredText
.. -*- coding: utf-8; mode: rst -*-
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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:function:: int ioctl( int fd, FE_SET_TONE, enum fe_sec_tone_mode *tone )
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:name: FE_SET_TONE
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Arguments
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=========
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``fd``
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File descriptor returned by :ref:`open() <frontend_f_open>`.
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``tone``
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pointer to enum :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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.. c:type:: fe_sec_tone_mode
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.. flat-table:: enum fe_sec_tone_mode
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:header-rows: 1
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:stub-columns: 0
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- .. row 1
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- ID
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- Description
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- .. row 2
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- .. _SEC-TONE-ON:
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``SEC_TONE_ON``
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- Sends a 22kHz tone burst to the antenna
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- .. row 3
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- .. _SEC-TONE-OFF:
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``SEC_TONE_OFF``
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- Don't send a 22kHz tone to the antenna (except if the
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FE_DISEQC_* ioctls are called)
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Return Value
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============
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On success 0 is returned, on error -1 and the ``errno`` variable is set
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appropriately. The generic error codes are described at the
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:ref:`Generic Error Codes <gen-errors>` chapter.
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