DTE to Modem
Modem to DTE Description and Interpretation
#CLS=8 Configure the modem for Voice Mode.
OK The modem confirms command reception, and is now set
up for voice.
#VBS=4 The DTE asks for 4-bit compression. The data from the
DTE needs to travel at 38,400 bits/s since after start
and stop bits are added, the speed increases to 36,000
bits/s.
OK The modem is configured for 4-bit compression.
#BDR=16 The DTE knows that compression requires a 38,400
bits/s speed, so it forces this as the new speed. (For
example, the DTE was sending all commands, including
this one, at 4800 bits/s.)
OK This OK message is sent at 4800 bits/s, but the modem
switches to 38,400 bits/s. All subsequent commands are
assumed to be sent at 38,400 bits/s. The DTE should
switch after the <CR><LF>following the OK.
The S30 timer is now active.
#VSD=1 This enables silence insertion.
OK The modem confirms command reception. (#VSS is
unnecessary playback.)
#VLS=2 Select the speaker as the output device to be used by
the modem.
VCON The modem confirms command reception, and enters
Online Voice Command Mode. Since this is an output
only device, nothing more can happen yet.
#VTX This tells the modem that the DTE is ready to send
voice per the current compression/sampling settings.
CONNECT The modem tells the DTE that it can now send data.
The modem enters Voice Transmit Mode and ADPCM data
flow begins.
<Data> The DTE sends data. The modem waits one second before
starting to transmit to the speaker to ensure
uninterrupted data flow. If the voice transmit buffer
runs empty, the transmitter is disabled.
<DLE> The DTE has finished its transmission and now
<ETX> instructs the modem to enter Online Voice Command Mode
after emptying the voice transmit buffer.
VCON The modem tells the DTE it is done. If the DTE sends
the <DLE><ETX>before the modem has finished
transmitting all the data in its buffer, the DTE must
wait for this response. (VCON indicates that the DTE
can send more data at any time with #VTX.)
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