# DVB Frontend API

The DVB frontend device controls the tuner and DVB demodulator hardware. It can be accessed through /dev/dvb/adapter0/frontend0. Data types and and ioctl definitions can be accessed by including linux/dvb/frontend.h in your application.

DVB frontends come in three varieties: DVB-S (satellite), DVB-C (cable) and DVB-T (terrestrial). Transmission via the internet (DVB-IP) is not yet handled by this API but a future extension is possible. For DVB-S the frontend device also supports satellite equipment control (SEC) via DiSEqC and V-SEC protocols. The DiSEqC (digital SEC) specification is available from Eutelsat.

Note that the DVB API may also be used for MPEG decoder-only PCI cards, in which case there exists no frontend device.

# Frontend Data Types

## Frontend type

For historical reasons, frontend types are named by the type of modulation used in transmission. The fontend types are given by fe_type_t type, defined as:

### Frontend types

&cs-def;
fe_type | Description | DTV_DELIVERY_SYSTEM equivalent type
--- | --- | ---
`FE_QPSK` | For DVB-S standard | `SYS_DVBS`
`FE_QAM` | For DVB-C annex A standard | `SYS_DVBC_ANNEX_A`
`FE_OFDM` | For DVB-T standard | `SYS_DVBT`
`FE_ATSC` | For ATSC standard (terrestrial) or for DVB-C Annex B (cable) used in US. | `SYS_ATSC` (terrestrial) or `SYS_DVBC_ANNEX_B` (cable)

Newer formats like DVB-S2, ISDB-T, ISDB-S and DVB-T2 are not described at the above, as they're supported via the new FE_GET_PROPERTY/FE_GET_SET_PROPERTY ioctl's, using the DTV_DELIVERY_SYSTEM parameter.

The usage of this field is deprecated, as it doesn't report all supported standards, and will provide an incomplete information for frontends that support multiple delivery systems. Please use DTV_ENUM_DELSYS instead.

## frontend capabilities

Capabilities describe what a frontend can do. Some capabilities can only be supported for a specific frontend type.

    	typedef enum fe_caps {
    	FE_IS_STUPID                  = 0,
    	FE_CAN_INVERSION_AUTO         = 0x1,
    	FE_CAN_FEC_1_2                = 0x2,
    	FE_CAN_FEC_2_3                = 0x4,
    	FE_CAN_FEC_3_4                = 0x8,
    	FE_CAN_FEC_4_5                = 0x10,
    	FE_CAN_FEC_5_6                = 0x20,
    	FE_CAN_FEC_6_7                = 0x40,
    	FE_CAN_FEC_7_8                = 0x80,
    	FE_CAN_FEC_8_9                = 0x100,
    	FE_CAN_FEC_AUTO               = 0x200,
    	FE_CAN_QPSK                   = 0x400,
    	FE_CAN_QAM_16                 = 0x800,
    	FE_CAN_QAM_32                 = 0x1000,
    	FE_CAN_QAM_64                 = 0x2000,
    	FE_CAN_QAM_128                = 0x4000,
    	FE_CAN_QAM_256                = 0x8000,
    	FE_CAN_QAM_AUTO               = 0x10000,
    	FE_CAN_TRANSMISSION_MODE_AUTO = 0x20000,
    	FE_CAN_BANDWIDTH_AUTO         = 0x40000,
    	FE_CAN_GUARD_INTERVAL_AUTO    = 0x80000,
    	FE_CAN_HIERARCHY_AUTO         = 0x100000,
    	FE_CAN_8VSB                   = 0x200000,
    	FE_CAN_16VSB                  = 0x400000,
    	FE_HAS_EXTENDED_CAPS          = 0x800000,
    	FE_CAN_MULTISTREAM            = 0x4000000,
    	FE_CAN_TURBO_FEC              = 0x8000000,
    	FE_CAN_2G_MODULATION          = 0x10000000,
    	FE_NEEDS_BENDING              = 0x20000000,
    	FE_CAN_RECOVER                = 0x40000000,
    	FE_CAN_MUTE_TS                = 0x80000000
    	} fe_caps_t;

## frontend information

Information about the frontend ca be queried with FE_GET_INFO.

    	struct dvb_frontend_info {
    	char       name[128];
    	fe_type_t  type;
    	uint32_t   frequency_min;
    	uint32_t   frequency_max;
    	uint32_t   frequency_stepsize;
    	uint32_t   frequency_tolerance;
    	uint32_t   symbol_rate_min;
    	uint32_t   symbol_rate_max;
    	uint32_t   symbol_rate_tolerance;     /⋆ ppm ⋆/
    	uint32_t   notifier_delay;            /⋆ ms ⋆/
    	fe_caps_t  caps;
    	};

## diseqc master command

A message sent from the frontend to DiSEqC capable equipment.

    	struct dvb_diseqc_master_cmd {
    	uint8_t msg [6]; /⋆  { framing, address, command, data[3] } ⋆/
    	uint8_t msg_len; /⋆  valid values are 3...6  ⋆/
    	};

## diseqc slave reply

A reply to the frontend from DiSEqC 2.0 capable equipment.

    	struct dvb_diseqc_slave_reply {
    	uint8_t msg [4]; /⋆  { framing, data [3] } ⋆/
    	uint8_t msg_len; /⋆  valid values are 0...4, 0 means no msg  ⋆/
    	int     timeout; /⋆  return from ioctl after timeout ms with ⋆/
    	};                       /⋆  errorcode when no message was received  ⋆/

## diseqc slave reply

The voltage is usually used with non-DiSEqC capable LNBs to switch the polarzation (horizontal/vertical). When using DiSEqC epuipment this voltage has to be switched consistently to the DiSEqC commands as described in the DiSEqC spec.

    	typedef enum fe_sec_voltage {
    	SEC_VOLTAGE_13,
    	SEC_VOLTAGE_18
    	} fe_sec_voltage_t;

## SEC continuous tone

The continuous 22KHz tone is usually used with non-DiSEqC capable LNBs to switch the high/low band of a dual-band LNB. When using DiSEqC epuipment this voltage has to be switched consistently to the DiSEqC commands as described in the DiSEqC spec.

    	typedef enum fe_sec_tone_mode {
    	SEC_TONE_ON,
    	SEC_TONE_OFF
    	} fe_sec_tone_mode_t;

## SEC tone burst

The 22KHz tone burst is usually used with non-DiSEqC capable switches to select between two connected LNBs/satellites. When using DiSEqC epuipment this voltage has to be switched consistently to the DiSEqC commands as described in the DiSEqC spec.

    	typedef enum fe_sec_mini_cmd {
    	SEC_MINI_A,
    	SEC_MINI_B
    	} fe_sec_mini_cmd_t;

## frontend status

Several functions of the frontend device use the fe_status data type defined by

    typedef enum fe_status {
    	FE_HAS_SIGNAL		= 0x01,
    	FE_HAS_CARRIER		= 0x02,
    	FE_HAS_VITERBI		= 0x04,
    	FE_HAS_SYNC		= 0x08,
    	FE_HAS_LOCK		= 0x10,
    	FE_TIMEDOUT		= 0x20,
    	FE_REINIT		= 0x40,
    } fe_status_t;

to indicate the current state and/or state changes of the frontend hardware:

FE_HAS_SIGNAL | The frontend has found something above the noise level
FE_HAS_CARRIER | The frontend has found a DVB signal
FE_HAS_VITERBI | The frontend FEC inner coding (Viterbi, LDPC or other inner code) is stable
FE_HAS_SYNC | Synchronization bytes was found
FE_HAS_LOCK | The DVB were locked and everything is working
FE_TIMEDOUT | no lock within the last about 2 seconds
FE_REINIT | The frontend was reinitialized, application is recommended to reset DiSEqC, tone and parameters

## frontend parameters

The kind of parameters passed to the frontend device for tuning depend on the kind of hardware you are using.

The struct `dvb_frontend_parameters` uses an union with specific per-system parameters. However, as newer delivery systems required more data, the structure size weren't enough to fit, and just extending its size would break the existing applications. So, those parameters were replaced by the usage of `FE_GET_PROPERTY/FE_SET_PROPERTY` ioctl's. The new API is flexible enough to add new parameters to existing delivery systems, and to add newer delivery systems.

So, newer applications should use `FE_GET_PROPERTY/FE_SET_PROPERTY` instead, in order to be able to support the newer System Delivery like DVB-S2, DVB-T2, DVB-C2, ISDB, etc.

All kinds of parameters are combined as an union in the FrontendParameters structure:

    struct dvb_frontend_parameters {
    	uint32_t frequency;     /⋆ (absolute) frequency in Hz for QAM/OFDM ⋆/
    				/⋆ intermediate frequency in kHz for QPSK ⋆/
    	fe_spectral_inversion_t inversion;
    	union {
    		struct dvb_qpsk_parameters qpsk;
    		struct dvb_qam_parameters  qam;
    		struct dvb_ofdm_parameters ofdm;
    		struct dvb_vsb_parameters  vsb;
    	} u;
    };

In the case of QPSK frontends the `frequency` field specifies the intermediate frequency, i.e. the offset which is effectively added to the local oscillator frequency (LOF) of the LNB. The intermediate frequency has to be specified in units of kHz. For QAM and OFDM frontends the `frequency` specifies the absolute frequency and is given in Hz.

### QPSK parameters

For satellite QPSK frontends you have to use the `dvb_qpsk_parameters` structure:

     struct dvb_qpsk_parameters {
    	 uint32_t        symbol_rate;  /⋆ symbol rate in Symbols per second ⋆/
    	 fe_code_rate_t  fec_inner;    /⋆ forward error correction (see above) ⋆/
     };

### QAM parameters

for cable QAM frontend you use the `dvb_qam_parameters` structure:

     struct dvb_qam_parameters {
    	 uint32_t         symbol_rate; /⋆ symbol rate in Symbols per second ⋆/
    	 fe_code_rate_t   fec_inner;   /⋆ forward error correction (see above) ⋆/
    	 fe_modulation_t  modulation;  /⋆ modulation type (see above) ⋆/
     };

### VSB parameters

ATSC frontends are supported by the `dvb_vsb_parameters` structure:

    struct dvb_vsb_parameters {
    	fe_modulation_t modulation;	/⋆ modulation type (see above) ⋆/
    };

### OFDM parameters

DVB-T frontends are supported by the `dvb_ofdm_parameters` structure:

     struct dvb_ofdm_parameters {
    	 fe_bandwidth_t      bandwidth;
    	 fe_code_rate_t      code_rate_HP;  /⋆ high priority stream code rate ⋆/
    	 fe_code_rate_t      code_rate_LP;  /⋆ low priority stream code rate ⋆/
    	 fe_modulation_t     constellation; /⋆ modulation type (see above) ⋆/
    	 fe_transmit_mode_t  transmission_mode;
    	 fe_guard_interval_t guard_interval;
    	 fe_hierarchy_t      hierarchy_information;
     };

### frontend spectral inversion

The Inversion field can take one of these values:

    typedef enum fe_spectral_inversion {
    	INVERSION_OFF,
    	INVERSION_ON,
    	INVERSION_AUTO
    } fe_spectral_inversion_t;

It indicates if spectral inversion should be presumed or not. In the automatic setting (`INVERSION_AUTO`) the hardware will try to figure out the correct setting by itself.

### frontend code rate

The possible values for the `fec_inner` field used on `struct dvb_qpsk_parameters` and `struct dvb_qam_parameters` are:

    typedef enum fe_code_rate {
    	FEC_NONE = 0,
    	FEC_1_2,
    	FEC_2_3,
    	FEC_3_4,
    	FEC_4_5,
    	FEC_5_6,
    	FEC_6_7,
    	FEC_7_8,
    	FEC_8_9,
    	FEC_AUTO,
    	FEC_3_5,
    	FEC_9_10,
    } fe_code_rate_t;

which correspond to error correction rates of 1/2, 2/3, etc., no error correction or auto detection.

### frontend modulation type for QAM, OFDM and VSB

For cable and terrestrial frontends, e. g. for `struct dvb_qpsk_parameters`, `struct dvb_qam_parameters` and `struct dvb_qam_parameters`, it needs to specify the quadrature modulation mode which can be one of the following:

     typedef enum fe_modulation {
    	QPSK,
    	QAM_16,
    	QAM_32,
    	QAM_64,
    	QAM_128,
    	QAM_256,
    	QAM_AUTO,
    	VSB_8,
    	VSB_16,
    	PSK_8,
    	APSK_16,
    	APSK_32,
    	DQPSK,
     } fe_modulation_t;

### More OFDM parameters

#### Number of carriers per channel

    typedef enum fe_transmit_mode {
    	TRANSMISSION_MODE_2K,
    	TRANSMISSION_MODE_8K,
    	TRANSMISSION_MODE_AUTO,
    	TRANSMISSION_MODE_4K,
    	TRANSMISSION_MODE_1K,
    	TRANSMISSION_MODE_16K,
    	TRANSMISSION_MODE_32K,
     } fe_transmit_mode_t;

#### frontend bandwidth

    typedef enum fe_bandwidth {
    	BANDWIDTH_8_MHZ,
    	BANDWIDTH_7_MHZ,
    	BANDWIDTH_6_MHZ,
    	BANDWIDTH_AUTO,
    	BANDWIDTH_5_MHZ,
    	BANDWIDTH_10_MHZ,
    	BANDWIDTH_1_712_MHZ,
    } fe_bandwidth_t;

#### frontend guard inverval

    typedef enum fe_guard_interval {
    	GUARD_INTERVAL_1_32,
    	GUARD_INTERVAL_1_16,
    	GUARD_INTERVAL_1_8,
    	GUARD_INTERVAL_1_4,
    	GUARD_INTERVAL_AUTO,
    	GUARD_INTERVAL_1_128,
    	GUARD_INTERVAL_19_128,
    	GUARD_INTERVAL_19_256,
    } fe_guard_interval_t;

#### frontend hierarchy

    typedef enum fe_hierarchy {
    	 HIERARCHY_NONE,
    	 HIERARCHY_1,
    	 HIERARCHY_2,
    	 HIERARCHY_4,
    	 HIERARCHY_AUTO
     } fe_hierarchy_t;

## frontend events

     struct dvb_frontend_event {
    	 fe_status_t status;
    	 struct dvb_frontend_parameters parameters;
     };

# Frontend Function Calls

## open()

DESCRIPTION

This system call opens a named frontend device (/dev/dvb/adapter0/frontend0) for subsequent use. Usually the first thing to do after a successful open is to find out the frontend type with FE_GET_INFO.

The device can be opened in read-only mode, which only allows monitoring of device status and statistics, or read/write mode, which allows any kind of use (e.g. performing tuning operations.)

In a system with multiple front-ends, it is usually the case that multiple devices cannot be open in read/write mode simultaneously. As long as a front-end device is opened in read/write mode, other open() calls in read/write mode will either fail or block, depending on whether non-blocking or blocking mode was specified. A front-end device opened in blocking mode can later be put into non-blocking mode (and vice versa) using the F_SETFL command of the fcntl system call. This is a standard system call, documented in the Linux manual page for fcntl. When an open() call has succeeded, the device will be ready for use in the specified mode. This implies that the corresponding hardware is powered up, and that other front-ends may have been powered down to make that possible.

SYNOPSIS

int open(const char ⋆deviceName, int flags);

PARAMETERS

const char *deviceName | Name of specific video device.
int flags | A bit-wise OR of the following flags:
| O_RDONLY read-only access
| O_RDWR read/write access
| O_NONBLOCK open in non-blocking mode
| (blocking mode is the default)

RETURN VALUE

ENODEV | Device driver not loaded/available.
EINTERNAL | Internal error.
EBUSY | Device or resource busy.
EINVAL | Invalid argument.

## close()

DESCRIPTION

This system call closes a previously opened front-end device. After closing a front-end device, its corresponding hardware might be powered down automatically.

SYNOPSIS

int close(int fd);

PARAMETERS

int fd | File descriptor returned by a previous call to open().

RETURN VALUE

EBADF | fd is not a valid open file descriptor.

## FE_READ_STATUS

DESCRIPTION

This ioctl call returns status information about the front-end. This call only requires read-only access to the device.

SYNOPSIS

int ioctl(int fd, int request = FE_READ_STATUS, fe_status_t ⋆status);

PARAMETERS

int fd | File descriptor returned by a previous call to open().
int request | Equals FE_READ_STATUS for this command.
struct fe_status_t *status | Points to the location where the front-end status word is to be stored.

RETURN VALUE

EBADF | fd is not a valid open file descriptor.
EFAULT | status points to invalid address.

## FE_READ_BER

DESCRIPTION

This ioctl call returns the bit error rate for the signal currently received/demodulated by the front-end. For this command, read-only access to the device is sufficient.

SYNOPSIS

int ioctl(int fd, int request = FE_READ_BER, uint32_t ⋆ber);

PARAMETERS

int fd | File descriptor returned by a previous call to open().
int request | Equals FE_READ_BER for this command.
uint32_t *ber | The bit error rate is stored into *ber.

&return-value-dvb;

## FE_READ_SNR

DESCRIPTION

This ioctl call returns the signal-to-noise ratio for the signal currently received by the front-end. For this command, read-only access to the device is sufficient.

SYNOPSIS

int ioctl(int fd, int request = FE_READ_SNR, int16_t ⋆snr);

PARAMETERS

int fd | File descriptor returned by a previous call to open().
int request | Equals FE_READ_SNR for this command.
int16_t *snr | The signal-to-noise ratio is stored into *snr.

&return-value-dvb;

## FE_READ_SIGNAL_STRENGTH

DESCRIPTION

This ioctl call returns the signal strength value for the signal currently received by the front-end. For this command, read-only access to the device is sufficient.

SYNOPSIS

int ioctl( int fd, int request = FE_READ_SIGNAL_STRENGTH, int16_t ⋆strength);

PARAMETERS

int fd | File descriptor returned by a previous call to open().
int request | Equals FE_READ_SIGNAL_STRENGTH for this command.
int16_t *strength | The signal strength value is stored into *strength.

&return-value-dvb;

## FE_READ_UNCORRECTED_BLOCKS

DESCRIPTION

This ioctl call returns the number of uncorrected blocks detected by the device driver during its lifetime. For meaningful measurements, the increment in block count during a specific time interval should be calculated. For this command, read-only access to the device is sufficient.
Note that the counter will wrap to zero after its maximum count has been reached.

SYNOPSIS

int ioctl( int fd, int request = FE_READ_UNCORRECTED_BLOCKS, uint32_t ⋆ublocks);

PARAMETERS

int fd | File descriptor returned by a previous call to open().
int request | Equals FE_READ_UNCORRECTED_BLOCKS for this command.
uint32_t *ublocks | The total number of uncorrected blocks seen by the driver so far.

&return-value-dvb;

## FE_SET_FRONTEND

DESCRIPTION

This ioctl call starts a tuning operation using specified parameters. The result of this call will be successful if the parameters were valid and the tuning could be initiated. The result of the tuning operation in itself, however, will arrive asynchronously as an event (see documentation for FE_GET_EVENT and FrontendEvent.) If a new FE_SET_FRONTEND operation is initiated before the previous one was completed, the previous operation will be aborted in favor of the new one. This command requires read/write access to the device.

SYNOPSIS

int ioctl(int fd, int request = FE_SET_FRONTEND, struct dvb_frontend_parameters ⋆p);

PARAMETERS

int fd | File descriptor returned by a previous call to open().
int request | Equals FE_SET_FRONTEND for this command.
struct dvb_frontend_parameters *p | Points to parameters for tuning operation.

&return-value-dvb;

EINVAL | Maximum supported symbol rate reached.

## FE_GET_FRONTEND

DESCRIPTION

This ioctl call queries the currently effective frontend parameters. For this command, read-only access to the device is sufficient.

SYNOPSIS

int ioctl(int fd, int request = FE_GET_FRONTEND, struct dvb_frontend_parameters ⋆p);

PARAMETERS

int fd | File descriptor returned by a previous call to open().
int request | Equals FE_SET_FRONTEND for this command.
struct dvb_frontend_parameters *p | Points to parameters for tuning operation.

&return-value-dvb;

EINVAL | Maximum supported symbol rate reached.

## FE_GET_EVENT

DESCRIPTION

This ioctl call returns a frontend event if available. If an event is not available, the behavior depends on whether the device is in blocking or non-blocking mode. In the latter case, the call fails immediately with errno set to EWOULDBLOCK. In the former case, the call blocks until an event becomes available.

The standard Linux poll() and/or select() system calls can be used with the device file descriptor to watch for new events. For select(), the file descriptor should be included in the exceptfds argument, and for poll(), POLLPRI should be specified as the wake-up condition. Since the event queue allocated is rather small (room for 8 events), the queue must be serviced regularly to avoid overflow. If an overflow happens, the oldest event is discarded from the queue, and an error (EOVERFLOW) occurs the next time the queue is read. After reporting the error condition in this fashion, subsequent FE_GET_EVENT calls will return events from the queue as usual.

For the sake of implementation simplicity, this command requires read/write access to the device.

SYNOPSIS

int ioctl(int fd, int request = QPSK_GET_EVENT, struct dvb_frontend_event ⋆ev);

PARAMETERS

int fd | File descriptor returned by a previous call to open().
int request | Equals FE_GET_EVENT for this command.
struct dvb_frontend_event *ev | Points to the location where the event,
| if any, is to be stored.

&return-value-dvb;

EWOULDBLOCK | There is no event pending, and the device is in non-blocking mode.
EOVERFLOW | Overflow in event queue - one or more events were lost.

## FE_GET_INFO

DESCRIPTION

This ioctl call returns information about the front-end. This call only requires read-only access to the device.

SYNOPSIS

int ioctl(int fd, int request = FE_GET_INFO, struct dvb_frontend_info ⋆info);

PARAMETERS

int fd | File descriptor returned by a previous call to open().
int request | Equals FE_GET_INFO for this command.
struct dvb_frontend_info *info | Points to the location where the front-end information is to be stored.

&return-value-dvb;

## FE_DISEQC_RESET_OVERLOAD

DESCRIPTION

If the bus has been automatically powered off due to power overload, this ioctl call restores the power to the bus. The call requires read/write access to the device. This call has no effect if the device is manually powered off. Not all DVB adapters support this ioctl.

SYNOPSIS

int ioctl(int fd, int request = FE_DISEQC_RESET_OVERLOAD);

PARAMETERS

int fd | File descriptor returned by a previous call to open().
int request | Equals FE_DISEQC_RESET_OVERLOAD for this command.

&return-value-dvb;

## FE_DISEQC_SEND_MASTER_CMD

DESCRIPTION

This ioctl call is used to send a a DiSEqC command.

SYNOPSIS

int ioctl(int fd, int request = FE_DISEQC_SEND_MASTER_CMD, struct dvb_diseqc_master_cmd ⋆cmd);

PARAMETERS

int fd | File descriptor returned by a previous call to open().
int request | Equals FE_DISEQC_SEND_MASTER_CMD for this command.
struct dvb_diseqc_master_cmd *cmd | Pointer to the command to be transmitted.

&return-value-dvb;

## FE_DISEQC_RECV_SLAVE_REPLY

DESCRIPTION

This ioctl call is used to receive reply to a DiSEqC 2.0 command.

SYNOPSIS

int ioctl(int fd, int request = FE_DISEQC_RECV_SLAVE_REPLY, struct dvb_diseqc_slave_reply ⋆reply);

PARAMETERS

int fd | File descriptor returned by a previous call to open().
int request | Equals FE_DISEQC_RECV_SLAVE_REPLY for this command.
struct dvb_diseqc_slave_reply *reply | Pointer to the command to be received.

&return-value-dvb;

## FE_DISEQC_SEND_BURST

DESCRIPTION

This ioctl call is used to send a 22KHz tone burst.

SYNOPSIS

int ioctl(int fd, int request = FE_DISEQC_SEND_BURST, fe_sec_mini_cmd_t burst);

PARAMETERS

int fd | File descriptor returned by a previous call to open().
int request | Equals FE_DISEQC_SEND_BURST for this command.
fe_sec_mini_cmd_t burst | burst A or B.

&return-value-dvb;

## FE_SET_TONE

DESCRIPTION

This call is used to set the generation of the continuous 22kHz tone. This call requires read/write permissions.

SYNOPSIS

int ioctl(int fd, int request = FE_SET_TONE, fe_sec_tone_mode_t tone);

PARAMETERS

int fd | File descriptor returned by a previous call to open().
int request | Equals FE_SET_TONE for this command.
fe_sec_tone_mode_t tone | The requested tone generation mode (on/off).

&return-value-dvb;

## FE_SET_VOLTAGE

DESCRIPTION

This call is used to set the bus voltage. This call requires read/write permissions.

SYNOPSIS

int ioctl(int fd, int request = FE_SET_VOLTAGE, fe_sec_voltage_t voltage);

PARAMETERS

int fd | File descriptor returned by a previous call to open().
int request | Equals FE_SET_VOLTAGE for this command.
fe_sec_voltage_t voltage | The requested bus voltage.

&return-value-dvb;

## FE_ENABLE_HIGH_LNB_VOLTAGE

DESCRIPTION

If high != 0 enables slightly higher voltages instead of 13/18V (to compensate for long cables). This call requires read/write permissions. Not all DVB adapters support this ioctl.

SYNOPSIS

int ioctl(int fd, int request = FE_ENABLE_HIGH_LNB_VOLTAGE, int high);

PARAMETERS

int fd | File descriptor returned by a previous call to open().
int request | Equals FE_SET_VOLTAGE for this command.
int high | The requested bus voltage.

&return-value-dvb;

## FE_SET_FRONTEND_TUNE_MODE

DESCRIPTION

Allow setting tuner mode flags to the frontend.

SYNOPSIS

int ioctl(int fd, int request = FE_SET_FRONTEND_TUNE_MODE, unsigned int flags);

PARAMETERS

unsigned int flags | FE_TUNE_MODE_ONESHOT When set, this flag will disable any zigzagging or other "normal" tuning behaviour. Additionally, there will be no automatic monitoring of the lock status, and hence no frontend events will be generated. If a frontend device is closed, this flag will be automatically turned off when the device is reopened read-write.

&return-value-dvb;

## FE_DISHNETWORK_SEND_LEGACY_CMD

DESCRIPTION

WARNING: This is a very obscure legacy command, used only at stv0299 driver. Should not be used on newer drivers. It provides a non-standard method for selecting Diseqc voltage on the frontend, for Dish Network legacy switches. As support for this ioctl were added in 2004, this means that such dishes were already legacy in 2004.

SYNOPSIS

int ioctl(int fd, int request = FE_DISHNETWORK_SEND_LEGACY_CMD, unsigned long cmd);

PARAMETERS

unsigned long cmd | sends the specified raw cmd to the dish via DISEqC.

&return-value-dvb;

&sub-dvbproperty;