1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 2 3.. _FE_SET_VOLTAGE: 4 5******************** 6ioctl FE_SET_VOLTAGE 7******************** 8 9Name 10==== 11 12FE_SET_VOLTAGE - Allow setting the DC level sent to the antenna subsystem. 13 14 15Synopsis 16======== 17 18.. c:function:: int ioctl( int fd, FE_SET_VOLTAGE, enum fe_sec_voltage voltage ) 19 :name: FE_SET_VOLTAGE 20 21 22Arguments 23========= 24 25``fd`` 26 File descriptor returned by :ref:`open() <frontend_f_open>`. 27 28``voltage`` 29 an integer enumered value described at :c:type:`fe_sec_voltage` 30 31 32Description 33=========== 34 35This ioctl allows to set the DC voltage level sent through the antenna 36cable to 13V, 18V or off. 37 38Usually, a satellite antenna subsystems require that the digital TV 39device to send a DC voltage to feed power to the LNBf. Depending on the 40LNBf type, the polarization or the intermediate frequency (IF) of the 41LNBf can controlled by the voltage level. Other devices (for example, 42the ones that implement DISEqC and multipoint LNBf's don't need to 43control the voltage level, provided that either 13V or 18V is sent to 44power up the LNBf. 45 46.. attention:: if more than one device is connected to the same antenna, 47 setting a voltage level may interfere on other devices, as they may lose 48 the capability of setting polarization or IF. So, on those cases, setting 49 the voltage to SEC_VOLTAGE_OFF while the device is not is used is 50 recommended. 51 52 53Return Value 54============ 55 56On success 0 is returned. 57 58On error -1 is returned, and the ``errno`` variable is set 59appropriately. 60 61Generic error codes are described at the 62:ref:`Generic Error Codes <gen-errors>` chapter. 63