10 Modem Control Signals

The ModemSignalListener Interface

The ModemSignalListener interface defines methods for being notified of modem signal changes.

The ModemSignalListener interface contains one method.

• void signalStateChanged(ModemSignalEvent event)

  This method is invoked when the state of a modem signal has changed.

The ModemSignalsControl Class

The ModemSignalsControl interface provides methods for controlling and monitoring modem signals.

The ModemSignalsControl class consists of six constants:

• static final int DTR_SIGNAL

  This constant represents the Data Terminal Ready (DTR) signal. This bit flag can be bitwise-combined (OR) with other signal bit flags.

• static final int DCD_SIGNAL

  This constant represents the Data Carrier Detect (DCD) signal. This bit flag can be bitwise-combined (OR) with other signal bit flags.

• static final int DSR_SIGNAL

  This constant represents the Data Set Ready (DSR) signal. This bit flag can be bitwise-combined (OR) with other signal bit flags.

• static final int RI_SIGNAL

  This constant represents the Ring Indicator (RI) signal. This bit flag can be bitwise-combined (OR) with other signal bit flags.

• static final int RTS_SIGNAL

  This constant represents the Ready To Send (RTS) signal. This bit flag can be bitwise-combined (OR) with other signal bit flags.

• static final int CTS_SIGNAL

  This constant represents the Clear To Send (CTS) signal. This bit flag can be bitwise-combined (OR) with other signal bit flags.

The ModemSignalsControl class also consists of three methods:

• void setSignalState(int signalID, boolean state) throws java.io.IOException,PeripheralNotAvailableException

  This method sets or clears the designated signal.

• boolean getSignalState(int signalID) throws java.io.IOException, PeripheralNotAvailableException

  This method returns the state of the designated signal.

• void setSignalChangeListener(ModemSignalListener listener, int signals) throws java.io.IOException, PeripheralNotAvailableException

  This method registers a ModemSignalListener instance which will get asynchronously notified when one of the designated signals changes. Notification will automatically begin after registration completes. If listener is null then the previously registered listener will be removed. Only one listener can be registered at a particular time.

The ModemSignalEvent Class

The ModemSignalEvent class encapsulates modem signal state changes. If signal state change events for the same peripheral are coalesced the value retained is that of the last occurrence.

The ModemSignalEvent class consists of two constants:

• protected int signalID

  This constant represents the signal ID.

• protected boolean signalState

  This constant represents the signal state.

The ModemSignalEvent class also consists of two constructors and several methods:

• public ModemSignalEvent(Peripheral peripheral, int signalID, boolean signalState)

  This constructor creates a new ModemSignalEvent with the specified value. It is then time-stamped with the current time.

• public ModemSignalEvent(Peripheral peripheral, int signalID, boolean signalState, long timeStamp, int timeStampMicros)

  This constructor creates a new ModemSignalEvent with the specified value and timestamp.

• public int getSignalID()

  This method returns the signal ID.

• public boolean getSignalState()

  This method returns the new signal state.