User`s manual

AT Command Reference Manual
7-36 1048
Table 7-9. Answer Call/Play Greeting/Record Message
DTE to Modem Modem to DTE Description and Interpretation
#CLS=8 Configure the modem for Voice Mode. Note that the #BDR setting is assumed to be
zero here, meaning that no time-out occurs forcing #CLS=0.
OK The modem agrees, and is now set up for voice.
#VBS=4 The DTE asks for 4-bit compression for greeting message playback (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.
#VSS =2 Sets silence detection sensitivity to midrange.
OK The modem confirms command reception.
#VLS=0 Select the telephone line as the source, ensuring that the modem is now on-hook.
DTMF detection is now off regardless of the previous setting of #VLS.
OK The modem confirms command reception, and it switches in the telephone line.
RING Some time later, we receive the first call. (Note that the modem also processes Caller
ID information at this time.)
#CLS=8 Configure the modem for Voice Mode again. Although the modem has already been so
configured, it is a good idea to select #CLS=8 directly following a RING because in
normal use, any S30 time-out or hang up during Voice Mode forces #CLS=0.
OK The modem agrees, and is now definitely set up for voice.
#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 9600 bps.)
OK This OK message is sent at 9600 bps, but the modem then switches to 38,400 bps. All
subsequent commands are assumed to be sent at 38,400 bps until either another
#BDR command is received or until the S30 timer expires. The S30 timer is now
activated, and the default is 60 seconds.
A The DTE tells the modem to answer.
VCON The modem is now in Online Voice Command Mode. DTMF and calling tone detection
is enabled.