PSB4860HV4.1 Lantiq, PSB4860HV4.1 Datasheet - Page 49

• Manufacturer Part Number: PSB4860HV4.1
• Manufacturer: Lantiq

Specifications of PSB4860HV4.1

• Lead Free Status / Rohs Status: Supplier Unconfirmed

2.1.6
The calling tone (CNG) detector can detect the standard calling tones of fax machines
or modems. This helps to distinguish voice messages from data transfers. The result of
the detector is available in the status register that can be read by the external controller
via the serial control interface (SCI). The CNG detector consists of two band-pass filters
with fixed center frequency of 1100 Hz and 1300 Hz.
Figure 25 CNG Detector - Block Diagram
Table 16 shows the available parameters.
Table 16
Register
CNGCTL
CNGCTL
CNGLEV
CNGBT
CNGRES
For a calling tone being detected, both the programmed minimum time and the minimum
signal level must be exceeded. Furthermore the input signal resolution can be reduced
by the RES parameter. Then the signal noise below the threshold RES is not regarded.
This can be useful in a noisy environment at low signal levels although the accuracy of
the detection decreases. As soon as a valid tone is detected, the status word of the is
updated. The status bits are defined as follows:
Table 17
Register # of Bits
STATUS 1
Note: STATUS:CNG is cleared only by disabling the module.
Data Sheet
CNG Detector
CNG Detector Registers
CNG Detector Result
# of Bits
1
5
16
16
16
I
1
Name
CNG
Name
EN
I1
MIN
TIME
RES
CNG Detector
1100 Hz 1300 Hz
Comment
Fax/Modem calling tone detected
Comment
CNG detector enable
Input signal selection
Minimum signal level
Minimum time of signal burst
Input signal resolution
49
SCI
PSB 4860
2000-01-14