Hayes Microcomputer Products RCV56HCF - Manual (Page 21)

RCV56HCF PCI/CardBus Modem Designer’s Guide
1129 ROCKWELL PROPRIETARY INFORMATION 2-3
2.6.1 Online Voice Command Mode
This mode results from the connection to the telephone line or a voice/audio I/O device (e.g., microphone, speaker, or
handset) through the use of the +FCLASS=8 and +VLS commands. After mode entry, AT commands can be entered without
aborting the connection.
2.6.2 Voice Receive Mode
This mode is entered when the +VRX command is active in order to record voice or audio data input at the RXA_L1 pin,
typically from a microphone/handset or the telephone line.
Received analog voice samples are converted to digital form and compressed for reading by the host. AT commands control
the codec bits-per-sample rate.
Received analog mono audio samples are converted to digital form and formatted into 8-bit unsigned linear or
µ
-Law PCM
format for reading by the host. AT commands control the bit length and sampling rate. Concurrent DTMF/tone detection is
available.
2.6.3 Voice Transmit Mode
This mode is entered when the +VTX command is active in order to playback voice or audio data to the TXA1_L1 output,
typically to a speaker/handset or to the telephone line. Digitized audio data is converted to analog form then output to the
TXA1_L1 output.
2.6.4 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.
2.6.5 Speakerphone Modes
Speakerphone modes are selected in voice mode with the following commands:
Speakerphone ON/OFF (+VSP). This command turns the Speakerphone function ON (+VSP = 1) or OFF (+VSP = 0).
Microphone Gain (+VGM)=<gain>. This command sets the microphone gain of the Speakerphone function. <gain> is an
unsigned octet where values greater than 128 indicate a gain larger than nominal and values smaller than 128 indicate a
gain smaller than nominal.
Speaker Gain (+VGS=<gain>). This command sets the speaker gain of the Speakerphone function. <gain> is an unsigned
octet where values greater than 128 indicate a gain larger than nominal and values smaller than 128 indicate a gain smaller
than normal.
2.7 SIMULTANEOUS AUDIO/VOICE AND DATA (AudioSpan)
The modem can operate in AudioSpan Mode if the remote modem is also configured for AudioSpan Mode operation.
AT commands are used to select the AudioSpan Mode, to enable automatic AudioSpan modulation selection or select a
specific AudioSpan modulation, and to enable AudioSpan data burst operation.
V.61 modulation supports 4800 bps data speed with audio, and a data-only speed of 4800 bps.
The AudioSpan audio interface defaults to the local handset connected to the modem and can be configured to interface
through the modem microphone and speaker pins to support use of a headset or a speakerphone.
2.8 HOST-BASED DSVD MODE
Host-based DSVD operation is enabled by the -SSE or -SMS command. In Host-based DSVD Mode, the modem supports
the transfer of data and voice occurs simultaneously during a data connection.
2.9 FULL-DUPLEX SPEAKERPHONE (FDSP) MODE
The modem operates in FDSP mode when +FCLASS=8 and +VSP=1 (see 2.6.5).
In FDSP Mode, speech from a microphone or handset is converted to digital form, shaped, and output to the telephone line
through the line interface circuit. Speech received from the telephone line is shaped, converted to analog form, and output to
the speaker or handset. Shaping includes both acoustic and line echo cancellation.
2.10 VOICEVIEW
Voice and data can be alternately sent and received in a time-multiplexed fashion over the telephone line whenever the
+FCLASS=80 command is active. This command and other VoiceView commands embedded in host communications