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Automatic Mode Selection
When automatic mode selection (AMS) is enabled, the
MDP configures itself to the highest compatible data rate
supported by the remote modem (AUTO bit). Automode
operation is supported in V.90, K56flex, V.34, V.32 bis,
V.32 V.22 bis, V.22, V.21, V.23, Bell 212A, and Bell 103
modes.
Automatic Rate Adaption (ARA)
In V.90, K56flex, V.34, and V.32 bis modes, automatic
rate adaption (ARA) can be enabled to select the highest
data rate possible based on the measured eye quality
monitor (EQM) (EARC bit). This selection occurs during
handshake/retrain and rate renegotiation.
Tone Generation
The MDP can generate single or dual voice-band tones
from 0 Hz to 3600 Hz with a resolution of 0.15 Hz and an
accuracy of ± 0.01%. Tones over 3000 Hz are attenuated.
DTMF tone generation allows the MDP to operate as a
programmable DTMF dialer.
Data Encoding
The data encoding conforms to ITU-T recommendations
V.90, V.34, V.32 bis, V.32, V.17, V.33, V.29, V.27 ter,
V.22 bis, V.22, V.23, or V.21, and is compatible with Bell
208, 212A, or 103, depending on the model and selected
configuration.
RTS - CTS Response Time
The response times of CTS relative to a corresponding
transition of RTS are listed in Table 3.
Transmit Level
The transmitter output level is selectable from -4 dBm to
-19 dBm (VAA = +3.3V) or 0 dBm to -15 dBm (VAA = +5V)
in 1 dB steps and is accurate to ±0.5 dB when used with
an external hybrid. The output level can also be fine tuned
by changing a gain constant in MDP DSP RAM. The
maximum V.34/V.32 bis/V.32 transmit level for acceptable
receive performance should not exceed -9 dBm.
Note:
In V.34 mode, the transmit level may be
automatically changed during the handshake. This
automatic adjustment of the transmit level may be
disabled via a parameter in DSP RAM.
Transmitter Timing
Transmitter timing is selectable between internal
(±0.01%), external, or slave.
Scrambler/Descrambler
A self-synchronizing scrambler/descrambler is used in
accordance with the selected configuration.
Answer Tone
When the NV25 bit is a zero, the MDP generates a 2100
Hz answer tone at the beginning of the answer handshake
for 5.0 seconds (V.8) or 3.6 seconds (V.32 bis, V.32, V.22
bis, V.22, V.23, and V.21). The answer tone has 180°
phase reversals every 0.45 second to disable network
echo cancellers (V.8, V.32 bis, V.32).
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RTS-CTS Response1
Configuration
V.90, K56flex, V.34,
V.32 bis, V.32
V.33/V.17 Long
V.33/V.17 Short
V.29
V.27 4800 Long
V.27 4800 Short
V.27 2400 Long
V.27 2400 Short
V.22 bis, V.22,
Bell 212A
V.21
V.23, Bell 103
Notes:
1. Times listed are CTS turn-on. The CTS OFF-to-ON
response time is host programmable in DSP RAM. (Full-
duplex modes only.)
2. Add echo protector tone duration plus 20 ms when echo
protector tone is used during turn-on.
3. Turn-off sequence consists of transmission of remaining
data and scrambled ones for controlled carrier operation.
CTS turn-off is less than 2 ms for all configurations.
4. Plus 20 ms of no transmitted energy.
5. N/A = not applicable.
Constant
Carrier
± 2 ms
N/A
N/A
N/A
N/A
N/A
N/A
N/A
± 2 ms
500 ms
210 ms
Controlled
Carrier
N/A
1393 ms2
142 ms2
253 ms2
708 ms2
50 ms2
943 ms2
67 ms2
270 ms
500 ms
210 ms
Turn-Off
Sequence3
N/A
15 ms4
15 ms4
12 ms
7 ms4
7 ms4
10 ms4
10 ms4
N/A
N/A
N/A
Receive Level
The MDP satisfies performance requirements for received
line signal levels from –9 dBm to –43 dBm measured at
the Receiver Analog (RXA) (TIP and RING) input (-15
dBm at RIN).
Note:
A 6 dB pad is required between TIP and RING and
the RIN input.
Receiver Timing
The timing recovery circuit can track a frequency error in
the associated transmit timing source of ±0.035% (V.22
bis) or ±0.01% (other configurations).
Carrier Recovery
The carrier recovery circuit can track a ±7 Hz frequency
offset in the received carrier.
Clamping
Received Data (RXD) is clamped to a constant mark
whenever the Received Line Signal Detector (~RLSD) is
off. ~RLSD can be clamped off (RLSDE bit).
CONEXANT [ CONEXANT SYSTEMS, INC ]
