¿Qué representan los diferentes estados de llamada en la pila de telefonía de Android?

Question

El interna clase Android com.android.internal.telephony.Call contiene una enumeración llamada Estado y se define de la siguiente manera:

public enum State { 
    IDLE, ACTIVE, HOLDING, DIALING, ALERTING, INCOMING, WAITING, DISCONNECTED, DISCONNECTING; 

    public boolean isAlive() { 
     return !(this == IDLE || this == DISCONNECTED || this == DISCONNECTING); 
    } 

    public boolean isRinging() { 
     return this == INCOMING || this == WAITING; 
    } 

    public boolean isDialing() { 
     return this == DIALING || this == ALERTING; 
    } 
} 

¿Qué representan los diferentes estados?

Answer 1

bien, esta es mi propio intento de responder a la pregunta:

/** Call is idle. */ 
IDLE, 
/** Call is active i.e. audio paths are connected. */ 
ACTIVE, 
/** We have placed the call on hold. */ 
HOLDING, 
/** Outgoing dialling call initiated. */ 
DIALING, 
/** Outgoing call is alerting receiving party. */ 
ALERTING, 
/** Incoming call ready for pickup. */ 
INCOMING, 
/** Incoming call is waiting for pickup, while another call is in progress. */ 
WAITING, 
/** Call is disconnected, by either party. */ 
DISCONNECTED, 
/** Call is currently being disconnected. */ 
DISCONNECTING; 

Answer 2

3GPP TS 27.007 version 13.5.0 Release 13 

List current calls +CLCC 

Command 
+CLCC 

Possible response(s) 
[+CLCC: <ccid1>,<dir>,<stat>,<mode>,<mpty>[,<number> 
,<type>[,<alpha>[,<priority>[,<CLI validity>]]]] 
[<CR><LF>+CLCC: <ccid2>,<dir>,<stat>,<mode>,<mpty>[, 
<number>,<type>[,<alpha>[,<priority>[,<CLI validity> 
]]]] 
[...]]] 
+CME ERROR: <err> 

<stat>: integer type (state of the call) 
0 active 
1 held 
2 dialing (MO call) 
3 alerting (MO call) 
4 incoming (MT call) 
5 waiting (MT call) 

My interpretation: 

0 active: call in progress (setup was successful) 
1 held: call on hold 
2 dialing (MO call): number dialed 
3 alerting (MO call): number dialed and the called party is alerted 
4 incoming (MT call): incoming call, ringtone played (AT RING notification) 
5 waiting (MT call): call waiting notification while another call is active (if call waiting feature enabled)