1 <refentry id="FE_SET_VOLTAGE">
3 <refentrytitle>ioctl FE_SET_VOLTAGE</refentrytitle>
8 <refname>FE_SET_VOLTAGE</refname>
9 <refpurpose>Allow setting the DC level sent to the antenna subsystem.</refpurpose>
15 <funcdef>int <function>ioctl</function></funcdef>
16 <paramdef>int <parameter>fd</parameter></paramdef>
17 <paramdef>int <parameter>request</parameter></paramdef>
18 <paramdef>&fe-sec-voltage; *<parameter>voltage</parameter></paramdef>
24 <title>Arguments</title>
27 <term><parameter>fd</parameter></term>
33 <term><parameter>request</parameter></term>
35 <para>FE_SET_VOLTAGE</para>
39 <term><parameter>pointer to &fe-sec-voltage;</parameter></term>
45 <title>Description</title>
47 <para>This ioctl allows to set the DC voltage level sent through the antenna
48 cable to 13V, 18V or off.</para>
49 <para>Usually, a satellital antenna subsystems require that the digital TV
50 device to send a DC voltage to feed power to the LNBf. Depending on the
51 LNBf type, the polarization or the intermediate frequency (IF) of the LNBf
52 can controlled by the voltage level. Other devices (for example, the ones
53 that implement DISEqC and multipoint LNBf's don't need to control the
54 voltage level, provided that either 13V or 18V is sent to power up the
56 <para>NOTE: if more than one device is connected to the same antenna,
57 setting a voltage level may interfere on other devices, as they may lose
58 the capability of setting polarization or IF. So, on those
59 cases, setting the voltage to SEC_VOLTAGE_OFF while the device is not is
60 used is recommended.</para>
65 <section id="fe-sec-voltage-t">
66 <title>enum fe_sec_voltage</title>
68 <table pgwide="1" frame="none" id="fe-sec-voltage">
69 <title>enum fe_status</title>
75 <entry>Description</entry>
80 <entry align="char">SEC_VOLTAGE_13</entry>
81 <entry align="char">Set DC voltage level to 13V</entry>
83 <entry align="char">SEC_VOLTAGE_18</entry>
84 <entry align="char">Set DC voltage level to 18V</entry>
86 <entry align="char">SEC_VOLTAGE_OFF</entry>
87 <entry align="char">Don't send any voltage to the antenna</entry>