DTE to Modem
Modem to DTE Description and Interpretation
#CLS=8 Configure the modem for Voice Mode.
OK The modem confirms command implemented, and is now
set up for voice.
#VBS=4 The DTE asks for 4-bit compression. The DTE needs to
work 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.
S30=60 DTE wants to insure that the modem can recover even
if DTE dies with the baud rate set to a speed which
cannot be speed sensed.
OK Modem now has deadman timer set to one minute. If no
activity takes place after a connection, or no DTE
activity takes place after #BDR is changed, the modem
reverts to #CLS=0, #BDR=0.
#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 2400 bits/s.)
OK The OK message is sent at 2400 bits/s, but the modem
then switches to 38,400 bits/s. All subsequent
commands are assumed to be sent at 38,400 bits/s. If
the DTE does not switch to 38,400 bits/s after
OK<CR><LF>, it will not recognize the data
stream coming from the modem. The S30 timer is now
active.
#VSP=20 The DTE changes its own speed to 38,400 bits/s and
sends this command to set up the silence detection
period for two seconds.
OK The modem agrees. When receiving voice data, two
seconds of silence terminates the Receive Mode. For
handset operation, this amounts to a hang up.
#VSD=1 This enables silence deletion.
OK The modem confirms command reception.
#VSS=1 The DTE has decided to use level 1 silence detection
sensitivity, meaning it is making it somewhat more
difficult to delete and compress silence for the
modem, but expects that when the user has hung up the
handset, the silence is indeed detected. The DTE has
tried to improve the quality of the message because it
knows this is a handset operation. Also, since silence
deletion has been enabled, the #VSP setting for
silence detection now becomes basically an inactivity
timer. If silence deletion is turned off here instead
of enabled, the #VSP timer is based upon average
energy readings from the modem.
OK The modem confirms command reception.
#VLS=? Find out what type of devices are supported by the
product.
0, 1, 2, 3, 4 The modem tells the DTE that is has a telephone line
OK with handset (#VLS=0), an input/output device such as
a handset or speakerphone (#VLS=1), and an output only
device such as a speaker.
#VLS=1 Select the handset as the input device to be used by
the modem.
VCON The modem agrees, switches out the telephone line,
switches in the handset, and the modem enters Online
Voice Command Mode. Since this is a handset, and since
the baud rate has been preselected with #BDR, this
also means that DTMF detection and reporting is now
enabled. The user can pick up the telephone and send
tones at this point, which are delivered as shielded
codes to the DTE, although the voice data is not yet
being passed.
#VRX This tells the modem that the DTE is ready to receive
a voice message at the current compression/sampling
settings.
CONNECT The modem tells the DTE that it can now expect data.
The modem enters Voice Receive Mode. DTMF monitoring
is still enabled as well as ADPCM data flow.
<Data> User says: "Hello, this is me, press * to skip
this message. I'm happy that you have called, so press
5 to send your FAX, or you can leave your message at
the beep."User then hangs up, the message is
buffered to the DTE, and the DTE waits for the message
to end. The DTE should have some predetermined limit.
Alternatively, the DTE can require the user to enter a
DTMF tone to terminate transmission of the message to
the DTE.
<DLE>q The modem has noticed (#VSP time out) that the user
has finished. The modem reports this while staying in
Voice Receive Mode. DTMF detection and reporting is
still active. The DTE now has the entire greeting
message on disk.
<DLE>* The user has inadvertently pressed the "*"
button, but the DTE is not interested in this
presently.
! The DTE issues a key abort to switch to Online Voice
Command Mode.
<DLE> The modem exists Voice Receive Mode and switches to
<ETX> Online Voice Command Mode.
VCON
#VLS=0 The DTE did not really have to do this, but wants to
make sure that it gets no more DTMF codes from the
handset. Selection of the telephone line here forces
the modem out of Online Voice Command Mode, which is
equivalent to hanging up.
OK
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