User`s manual

AT Command Reference Manual
1048 7-33
Table 7-7. Record a Greeting Message
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 (ADPCM). The DTE needs to work at 38,400 bps
since after start and stop bits are added, the speed increases to 36,000 bps.
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 Disconnect Inactivity timer set to 1 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 bps speed, so it forces this as the
new speed. (For this example, lets say that the DTE was sending all commands,
including this one, at 2400 bps.)
OK This OK message is sent at 2400 bps, but the modem then switches to 38,400 bps. All
subsequent commands are assumed to be sent at 38,400 bps. If the DTE does not
switch to 38,400 bps after the 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 bps and sends this command to set up the
silence detection period for 2 seconds.
OK The modem agrees. When receiving voice data, 2 seconds of silence terminates the
Receive Mode. For handset operation, this amounts to a hang up.
#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. 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
OK
The modem tells the DTE that is has a telephone line with handset (#VLS=0), an
input/output device such as a handset or speaker-phone (#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.