UX-A255U
B) Modem block
1) Facsimile Modem
The modem can operate at 14400, 12000, 9600, 7200, 4800, 2400, or
300 bps, and can perform HDLC framing per T.30 at all rates. A pro-
grammable DTMF detector, three programmable tone detectors, V.21
Channel 2 FSK 7E flag detector, Caller ID demodulator and ring detec-
tor are provided.
2) Voice and Audio Codecs
The voice coder/decoder (codec) compresses voice at an average rate of
2.9 kbps which provides 24 minutes of stored voice messages in 4 Mbits
of memory. But for UX-A255U, a part of memory is used for other usages.
So the total recording time is shortened at about 20 minutes. This voice
codec allows the host controller to efficiently store and playback digital
incoming messages (ICMs), outgoing messages (OGMs).
The ADPCM audio codec compresses audio signals (music/voice) at 32
kbps or 24 kbps and the PCM audio codec records audio signals at 128
kbps or 64 kbps for highest fidelity coding and reproduction.
Selectable error correction coding allows storage in audio grade RAMs
(ARAMs). Echo cancellation techniques employed during playback
allow DTMF tone and Type II Caller ID CAS detection during voice/audio
codec operation to support user selectable features. The coder can record
messages from the PIA or SIA. The decoder can playback messages to
the PIA or both the PIA and SIA. Dual/signal tone transmission is avail-
able when the decoder is disabled.
3) V.23 Full-duplex Modem and Caller ID
Both full-duplex transmit and receive (with asymmetric 1200/75 bps con-
nection) and half-duplex (1200 bps) asynchronous V.23 are supported,
as will as both serial and parallel interfaces to the modem. The V.23
algorithm includes an optional, programmable. receive compromise
equalizer which is active in both V.23 and Caller ID (V.23 Receive only)
modes.
Common applications for V.23 include France’s Minitel and Japan’s Lowest
Cost Routing.
5 – 4
4) Features
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Group 3 facsimile transmission/reception
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ITU-T V.17 and V.33
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ITU-T V.29, V.27 ter, T.30, V.21 Channel 2, T.4
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ITU-T V.17 and V.27 ter short train
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HDLC framing at all speeds
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Receive dynamic range: 0 dBm to -43 dBm
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Automatic adaptive equalization
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Fixed and programmable digital compromise equalization
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DTMF detect and tone detect
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ITU-T V.21 Channel 2 FSK 7E Flag Detect
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Ring detector
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Programmable transmits level
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Programmable single/dual tone transmission
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Voice codec
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24 minutes of voice storage per 4 Mbit memory
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Near toll quality voice recording and playback
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Programmable AGCs
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Programmable line/microphone input and line/speaker output filters
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Error correction coding allows ARAM usage
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DTMF detect, tone detect, and tone transmit
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Type II Caller ID CAS detection
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Pitch synchronized fast and slow playback
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Near-end echo cancellation
•
ADPCM Audio codec
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High fidelity recording and playback of audio signals
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32 kbps and 24 kbps
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Programmable AGCs
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Programmable line/microphone input and line/speaker output filters
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DTMF detect, tone detect, and tone transmit
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Type II Caller ID CAS detection
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Near-end echo cancellation
•
PCM audio codec
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128 kbps and 64 kbps
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DTMF detect and tone detect
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Type II Caller ID CAS detection
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Near-end echo cancellation
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V.23 and Type I Caller ID
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Full-duplex modes:
TX = 75 bps. RX = 1200 bps
TX = 1200 bps. RX = 75 bps
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Half-duplex mode:
TX = RX = 1200 bps
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Serial and parallel data modes
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Programmable parallel data mode
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5, 6, 7, or 8 data bits
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1 or 2 Stop bits
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Mark, Space, Even, or Odd Parity
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Break function
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Transmitter squelch
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Compromise equalizer
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3.3V/5V operation
