2.5.10. ioctl FE_SET_TONE

2.5.10.1. Name

FE_SET_TONE - Sets/resets the generation of the continuous 22kHz tone.

2.5.10.2. Synopsis

int ioctl(int fd, FE_SET_TONE, enum fe_sec_tone_mode *tone)

2.5.10.3. Arguments

fd

File descriptor returned by open().

tone

pointer to enum fe_sec_tone_mode

2.5.10.4. Description

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

Usually, satellite antenna subsystems require that the digital TV device to send a 22kHz tone in order to select between high/low band on some dual-band LNBf. It is also used to send signals to DiSEqC equipment, but this is done using the DiSEqC ioctls.

Attention

If more than one device is connected to the same antenna, setting a tone may interfere on other devices, as they may lose the capability of selecting the band. So, it is recommended that applications would change to SEC_TONE_OFF when the device is not used.

fe_sec_tone_mode

enum fe_sec_tone_mode

ID	Description
SEC_TONE_ON	Sends a 22kHz tone burst to the antenna
SEC_TONE_OFF	Don’t send a 22kHz tone to the antenna (except if the FE_DISEQC_* ioctls are called)

2.5.10.5. Return Value

On success 0 is returned, on error -1 and the errno variable is set appropriately. The generic error codes are described at the Generic Error Codes chapter.