Low Power V.22 bis Modem
CMX868
1.5.10.4 Receive Mode Register
Receive Mode Register: 16-bit write-only.
C-BUS address $E2
This register controls the CMX868 receive signal type and level.
All bits of this register are cleared to 0 by a General Reset command, or when b7 (Reset) of the General
Control Register is 1.
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Bit:
Rx mode = modem
Rx level
Eq
Descrambl
Start-stop/Synch
No. of bits and
parity
Rx mode = Tones detect
Rx mode = Disabled
Rx level
DTMF/Tones/Call Progress select
Set to 0000 0000 0000
Rx Mode Register b15-12: Rx mode
These 4 bits select the receive operating mode.
b15 b14 b13 b12
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
V.22 bis 2400 bps QAM
High band (Calling modem)
Low band (Answering modem)
High band (Calling modem)
Low band (Answering modem)
High band (Calling modem)
Low band (Answering modem)
High band (Calling modem)
Low band (Answering modem)
High band (Calling modem)
Low band (Answering modem)
1200 bps
“
V.22/Bell 212A 1200 bps DPSK
“
V.22 600 bps DPSK
“
V.21 300 bps FSK
“
Bell 103 300 bps FSK
“
V.23 FSK
“
75 bps
1200 bps
150 bps
Bell 202 FSK
“
DTMF, Programmed tone pair, Answer Tone, Call Progress detect
Receiver disabled
Rx Mode Register b11-9: Rx level
These three bits set the gain of the Rx Gain Control block.
b11
b10
b9
1
1
1
1
0
0
0
0
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
0
0dB
-1.5dB
-3.0dB
-4.5dB
-6.0dB
-7.5dB
-9.0dB
-10.5dB
ã 2004 CML Microsystems Plc
26
D/868/9
CMLMICRO [ CML MICROCIRCUITS ]
