call setup status indicator;
indicator <ind> values are 0 (no
active call setup), 1 (MT call is
ringing), 2 (MO call was
initiated), 3 (MO call ringing at
called party)
Next command causes all the indicators to be registered
AT+CIND=1,1,1,1,1,1,1,1,1
Next command causes all the indicators to be de-registered
AT+CIND=0,0,0,0,0,0,0,0,0
Next command to query the current value of all indicators
AT+CIND?
CIND: 4,0,1,0,0,0,0,0,2
OK