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1 | .. -*- coding: utf-8; mode: rst -*- |
2 | ||
3 | .. _FE_SET_VOLTAGE: | |
4 | ||
5 | ******************** | |
6 | ioctl FE_SET_VOLTAGE | |
7 | ******************** | |
8 | ||
15e7d615 | 9 | Name |
586027ce | 10 | ==== |
5377d91f | 11 | |
586027ce | 12 | FE_SET_VOLTAGE - Allow setting the DC level sent to the antenna subsystem. |
5377d91f | 13 | |
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14 | |
15 | Synopsis | |
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16 | ======== |
17 | ||
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18 | .. c:function:: int ioctl( int fd, FE_SET_VOLTAGE, enum fe_sec_voltage *voltage ) |
19 | :name: FE_SET_VOLTAGE | |
5377d91f | 20 | |
586027ce | 21 | |
15e7d615 | 22 | Arguments |
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23 | ========= |
24 | ||
25 | ``fd`` | |
26 | File descriptor returned by :ref:`open() <frontend_f_open>`. | |
27 | ||
5377d91f | 28 | ``voltage`` |
836cf1db | 29 | pointer to enum :c:type:`fe_sec_voltage` |
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30 | |
31 | Valid values are described at enum | |
836cf1db | 32 | :c:type:`fe_sec_voltage`. |
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33 | |
34 | ||
15e7d615 | 35 | Description |
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36 | =========== |
37 | ||
38 | This ioctl allows to set the DC voltage level sent through the antenna | |
39 | cable to 13V, 18V or off. | |
40 | ||
41 | Usually, a satellite antenna subsystems require that the digital TV | |
42 | device to send a DC voltage to feed power to the LNBf. Depending on the | |
43 | LNBf type, the polarization or the intermediate frequency (IF) of the | |
44 | LNBf can controlled by the voltage level. Other devices (for example, | |
45 | the ones that implement DISEqC and multipoint LNBf's don't need to | |
46 | control the voltage level, provided that either 13V or 18V is sent to | |
47 | power up the LNBf. | |
48 | ||
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49 | .. attention:: if more than one device is connected to the same antenna, |
50 | setting a voltage level may interfere on other devices, as they may lose | |
51 | the capability of setting polarization or IF. So, on those cases, setting | |
52 | the voltage to SEC_VOLTAGE_OFF while the device is not is used is | |
53 | recommended. | |
5377d91f | 54 | |
586027ce | 55 | |
15e7d615 | 56 | Return Value |
586027ce | 57 | ============ |
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58 | |
59 | On success 0 is returned, on error -1 and the ``errno`` variable is set | |
60 | appropriately. The generic error codes are described at the | |
61 | :ref:`Generic Error Codes <gen-errors>` chapter. |