1 .. Permission is granted to copy, distribute and/or modify this
2 .. document under the terms of the GNU Free Documentation License,
3 .. Version 1.1 or any later version published by the Free Software
4 .. Foundation, with no Invariant Sections, no Front-Cover Texts
5 .. and no Back-Cover Texts. A copy of the license is included at
6 .. Documentation/media/uapi/fdl-appendix.rst.
8 .. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
19 FE_SET_VOLTAGE - Allow setting the DC level sent to the antenna subsystem.
25 .. c:function:: int ioctl( int fd, FE_SET_VOLTAGE, enum fe_sec_voltage voltage )
33 File descriptor returned by :ref:`open() <frontend_f_open>`.
36 an integer enumered value described at :c:type:`fe_sec_voltage`
42 This ioctl allows to set the DC voltage level sent through the antenna
43 cable to 13V, 18V or off.
45 Usually, a satellite antenna subsystems require that the digital TV
46 device to send a DC voltage to feed power to the LNBf. Depending on the
47 LNBf type, the polarization or the intermediate frequency (IF) of the
48 LNBf can controlled by the voltage level. Other devices (for example,
49 the ones that implement DISEqC and multipoint LNBf's don't need to
50 control the voltage level, provided that either 13V or 18V is sent to
53 .. attention:: if more than one device is connected to the same antenna,
54 setting a voltage level may interfere on other devices, as they may lose
55 the capability of setting polarization or IF. So, on those cases, setting
56 the voltage to SEC_VOLTAGE_OFF while the device is not is used is
63 On success 0 is returned.
65 On error -1 is returned, and the ``errno`` variable is set
68 Generic error codes are described at the
69 :ref:`Generic Error Codes <gen-errors>` chapter.