CX81801 Просмотр технического описания (PDF) - Conexant Systems

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CX81801

V.92/V.34/V.32bis Modem in 128-Pin TQFP with CX20493 SmartDAA® and Optional CX20442 Voice Codec

Conexant Systems 

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CX81801-7x/8x SmartV.XX Modem Data Sheet

Received analog mono audio samples are converted to digital form and formatted into 8-

bit unsigned linear PCM format for reading by the host. AT commands control the bit

length and sampling rate. Concurrent DTMF/tone detection is available at the 8 kHz

sample rate.

Voice Transmit Mode

This mode is entered when the +VTX command is active in order to playback voice or

audio data to the TXA output, typically to a speaker/handset or to the telephone line.

Digitized voice data is decompressed and converted to analog form at the original

compression quantization sample-per-bits rate then output to the TXA output.

Digitized audio data is converted to analog form then output to the TXA output.

Full-Duplex Receive and Transmit Mode

This mode is entered when the +VTR command is active in order to concurrently receive

and transmit voice.

Audio Mode

The audio mode enables the host to transmit and receive 8-bit audio signals. In this mode,

the modem directly accesses the internal analog-to-digital (A/D) converter (ADC) and the

digital-to-analog (D/A) converter (DAC). Incoming analog audio signals can then be

converted to digital format and digital signals can be converted to analog audio output.

Tone Detectors

The tone detector signal path is separate from the main received signal path thus enabling

tone detection to be independent of the configuration status. In Tone Mode, all three tone

detectors are operational.

Speakerphone Mode

Speakerphone mode is controlled in voice mode with the following commands:

Use Speakerphone After Dialing or Answering (+VSP=1). +VSP=1 selects

speakerphone mode while in +FCLASS=8 mode. Speakerphone operation is entered

during Voice Online Command mode after completing dialing or answering.

Speakerphone Settings. The +VGM and +VGS commands can be used to control the

microphone gain and speaker volume, respectively. VGM and +VGS commands are valid

only after the modem has entered the Voice Online mode while in the +VSP=1 setting.

V.80 Synchronous Access Mode (SAM) - Video Conferencing

V.80 Synchronous Access Mode between the modem and the host/DTE is provided for

host-controlled communication protocols, e.g., H.324 video conferencing applications.

Voice-call-first (VCF) before switching to a videophone call is also supported.

102199B

Conexant

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