FM336 V.34/Group 3 High Perform ance Fax M odem Fam ily
4
Conexant
100086B
Technical Specifications
The single device modem provides the processing
core for a complet e facsimile modem design.
Configurations and Rates
The selectable modem c onfigurations, signaling r ates,
and data rates are listed in Table 2.
Automatic Mode Selection (-D / -D90)
When Automatic M ode S elec tion (AMS) is enabled,
the modem configures itself to the highest compatible
data rate support ed by the remote modem. A utomode
operation is supported in V .90 (-D90 only), V.34,
V.32 bis, V. 32, V.22 bis, V. 22, V.21, V. 23, Bell 212A,
and Bell 103 modes.
Automatic Rate Adaptation
In V.34 duplex, V .34 half-duplex, and V. 32 bis modes,
Automatic Rat e A daptation (ARA) can be enabled to
select the optim al highes t acceptable data rate based
on the Eye Quality M onitor (EQM). This selection
occurs during star tup.
Two ARA modes are available. ARA in ROM is an
adaptive selection made by the modem based upon a
fixed ROM table. ARA in RAM is based on the hos t
programmable RAM table and c an be changed by the
user.
Data Encoding (-D / -D90)
The data encoding confor m s to ITU-T
recommendations V.90 (-D90 only), V.34, V.32 bis,
V.32, V.17, 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 configuration.
Tone Generation and Supervisory Tone Detection
The modem can generate s ingle or dual voice-band
tones from 0 Hz to 3600 Hz with a resolution of
0.15 Hz and an accuracy of ± 0.01%. T ones ov er
3000 Hz are attenuated. DTMF tone gener ation allows
the modem to operat e as a pr ogrammable DTMF
dialer.
Three parallel tone detec tors (A, B, and C) are
provided for supervi s or y tone detection. T he s ignal
path to these det ec tors is separate from the main
received signal path.
Each tone detect or c ons is ts of two casc aded s ec ond
order IIR biquad filters. The coefficients are host
programmable. Each fourth order filter is followed by a
level detector which has hos t programmable turn- on
and turn-off thresholds allowing hysteres is . A pre-filter
and squarer precede tone det ec tor C. This cir c uit is
useful for detec ting a tone with a frequenc y equal to
the difference between two tones that may be
simultaneously present on the line. The squar er m ay
be disabled by the SQDI S bit causing tone detect or C
to be an eight-order f ilter. The tone detectors are
disabled in data mode.
The tone detect ion s am ple r ate is 9600 Hz in V.8 and
V.34 modes and is 7200 Hz in non-V .34 modes. The
default call progress filter coeff ic ients are based on a
7200 Hz sampling rate and apply t o non- V .34 modes
only. The maximum detection bandwidth is equal t o
one-half the sample rate.
Auto-Dialing and Auto-Answering Control
Features are prov ided to allow the host to per form
auto-dialing and auto-answering. These funct ions
include DTMF or pulse dialing, ring detection, and a
comprehensive superv is or y tone detection scheme.
The major control par ameters are host pr ogr am m able.
Transmitted Data Spectrum
The transmit ter spectrum is s haped by r ais ed c os ine
filter functions, either the square root of 12.5% ( V .34,
V.32 bis, V. 32) , 20% (V.17 and V.29) , 50% (V.27 ter,
Bell 208), or 75% (V. 22 bis , Bell 212A).
Transmit L evel
The transmit ter output level is selectable from 0 dBm
to –15 dBm in 1-dB steps and is accur ate to ±0.5 dB
when used with an external hybr id. The output level
can also be tuned by changing a gain constant in the
modem DSP RAM. The maximum V.34 transmit level
for acceptable rec eiv e per formance should not exc eed
–9 dBm.
Answer Tone (-D / -D90)
When the NV25 bit is a z er o, the modem generates a
2100 Hz answer tone at t he beginning of the answer
handshake for 5.0 sec onds (V.8) or 3.6 sec onds ( V .32
bis, V.32, V .22 bis, V.22, V .23, and V.21). The answer
tone has 180° phase revers als ev er y 0.45 seconds to
disable network echo canceller s (V.8, V.32 bis , V.32).
Receive Level
The modem satisfies performance r equir em ents for
received line signal levels fr om 0 dB m to –43 dBm
measured at the receiver analog (TIP and RING)
input in V.17, V.29, V.27 ter, and DTMF modes. In
V.90, V.34, V.32 bis, V. 32, V.22 bis, V.22, and V.23
modes, the receiv e lev el r ange is from –9 dBm
(–15 dBm at RIN) to –43 dBm .