What does the different Call states in the Android telephony stack represent?

Question

The internal Android class com.android.internal.telephony.Call contains an enum called State and defined as follows:

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;
    }
}

What does the different states represent?

Answer 1

Okay, this is my own attempt at answering the question:

/** 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;