Is your question about Bluetooth HandsFree profile?
To get a list of current calls HandsFree unit (HF, your device) sends AT+CLCC command. Audio Gateway (AG, your smartphone) sends back a sequence of call information records (if there is(are) some call(s) in progress) and when sends OK:
+CLCC: <idx>,<dir>,<status>,<mode>,<mprty>[,<number>,<type>]
...
+CLCC: <idx>,<dir>,<status>,<mode>,<mprty>[,<number>,<type>]
OK
You can read about meaning and possible values of fields in Bluetooth HandsFree or 3GPP 27.007 specification. Do you have a log?
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