The LINECALLSTATE_ bit-flag constants describe the call states a call can be
The call is idle
no call exists.
The call is being offered to the station, signaling the arrival of a new call.
In some environments, a call in the offering state does not automatically
alert the user because alerting is done by the switch instructing the line to ring.
It does not affect any call states.
The call was offering and has been accepted. This indicates to other
(monitoring) applications that the current owner application has claimed responsibility
for answering the call. In ISDN, this also initiates alerting to both parties.
The call is receiving a dial tone from the switch, which means that the switch
is ready to receive a dialed number.
Destination address information (a phone number) is being sent to the switch
over the call. Note that lineGenerateDigits
does not place the line into the dialing
The call is receiving ringback from the called address. Ringback indicates
that the other station has been reached and is being alerted.
The call is receiving a busy tone. A busy tone indicates that the call cannot
either a circuit (trunk) or the remote party's station are in use.
Special information is sent by the network. Special information is typically
sent when the destination cannot be reached.
The call has been established and the connection is made. Information is able
to flow over the call between the originating address and the destination
Dialing has completed and the call is proceeding through the switch or
The call is on hold by the switch.
The call is currently a member of a multi-party conference call.
The call is currently on hold while it is being added to a conference.
The call is currently on hold awaiting transfer to another number.
The remote party has disconnected from the call.
The state of the call is not known. This may be due to limitations of the
call-progress detection implementation.
The high-order 8 bits can define a device-specific substate of any of the
predefined states, provided that one of the LINECALLSTATE_ bits defined above is
also set. The low-order 24 bits are reserved for predefined states.
The LINECALLSTATE_ constants are used as parameters by the LINE_CALLSTATE
message sent to the application. The message carries the new call state that
the call transitioned to. These constants are also used as fields in the LINECALLSTATUS
structure returned by the lineGetCallStatus
- Software for developers
Software for Android Developers
- More information resources
Unix Manual Pages