Low Power V.22 bis Modem
CMX868
In QAM or DPSK Rx modem modes b2-0 of the Status Register contain a value indicative of the
received signal BER, see Figure 11. In Rx FSK modem modes bits 2 and 1 will be zero and b0
will show the output of the frequency demodulator, updated at 8 times the nominal data rate.
Figure 10b Operation of Status Register in DTMF Rx Mode
b3 b2 b1 b0 Low frequency (Hz)
High frequency
(Hz)
Keypad symbol
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
941
697
697
697
770
770
770
852
852
852
941
941
941
697
770
852
1633
1209
1336
1477
1209
1336
1477
1209
1336
1477
1336
1209
1477
1633
1633
1633
D
1
2
3
4
5
6
7
8
9
0
*
#
A
B
C
Received DTMF Code: b3-0 of Status Register
ã 2004 CML Microsystems Plc
31
D/868/9
CMLMICRO [ CML MICROCIRCUITS ]
