Maxim Integrated 73M1822/73M1922 Control Module - Manual (Page 57)

UG_1x22_053 73M1822/73M1922 Control Module User Guide
Rev. 1.0 57
6.9.2 M1X22_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 M1X22_BTONE_FILTER _IOWR(0xA4,0xC3,unsigned int)
Prototype
int ioctl (
int chan_fd,
int M1X22_BTONE_FILTER,
unsigned long param );
Parameters
Data Type Name Description
int chan_fd Channel descriptor.
int M1X22_BTINE_FILTER I/O control identifier for this operation.
unsigned long param Pointer to the M1X22_BTONE_FILTER_t
structure.
Return Values
Data Type Description
int -EFAULT – Failed to perform billing tone filter.
0 – Successful.