cx20493-35/app Conexant Systems, Inc., cx20493-35/app Datasheet - Page 29

• Manufacturer Part Number: cx20493-35/app
• Description: With Cx20493 Smartdaa?
• Manufacturer: Conexant Systems, Inc.

2.10.3
2.10.4
2.10.5
2.10.6
2.10.7
2.11
102247B
CX81801-7x/8x SmartV.XX Modem in 128-Pin LQFP with CX20493 in 32-Pin LQFP Data Sheet
Voice Transmit Mode
Full-Duplex Receive and Transmit Mode
Audio Mode
Tone Detectors
Speakerphone Mode
V.80 Synchronous Access Mode (SAM) - Video Conferencing
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.
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.
This mode is entered when the +VTR command is active in order to concurrently receive
and transmit voice.
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.
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 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 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.
Conexant
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