Maxim Integrated 73M1866B/73M1966B Reference Driver - Manual (Page 68)

73M1866B/73M1966B Reference Driver User Guide UG_1x66B_015
68 Rev. 2.7
6.9.2 M1966_BTONE_FILTER
Description
Large amplitude out-of-band tones can be used to measure call duration and to allow remote central
office to determine the duration of the call for billing purposes. These tones can saturate or distort the
input signal, thus, it is important to be able to reject them. This IOCTL provides the ability to filter out the
billing tone.
#define M1966_BTONE_FILTER _IOWR(0xA4,0xC3,unsigned int)
Prototype
int ioctl (
int chan_fd,
int M1966_BTONE_FILTER,
unsigned long param );
Parameters
Data Type Name Description
int chan_fd Channel descriptor.
int M1966_BTINE_FILTER I/O control identifier for this operation.
unsigned long param Pointer to structure X.
Return Values
Data Type Description
int -EFAULT – Failed to perform billing tone filter.
0 – Successful.