diff --git a/src/main/java/com/fazecast/jSerialComm/SerialPort.java b/src/main/java/com/fazecast/jSerialComm/SerialPort.java
index aa08eb6..8a80f9b 100644
--- a/src/main/java/com/fazecast/jSerialComm/SerialPort.java
+++ b/src/main/java/com/fazecast/jSerialComm/SerialPort.java
@@ -559,6 +559,7 @@ public final class SerialPort
 	private volatile SerialPortDataListener userDataListener = null;
 	private volatile SerialPortEventListener serialEventListener = null;
 	private volatile String comPort, friendlyName, portDescription, portLocation;
+	// many of the fields here are accessed by C code
 	private volatile boolean eventListenerRunning = false, disableConfig = false, disableExclusiveLock = false;
 	private volatile boolean rs485Mode = false, rs485ActiveHigh = true, rs485RxDuringTx = false, rs485EnableTermination = false;
 	private volatile boolean isRtsEnabled = true, isDtrEnabled = true, autoFlushIOBuffers = false, requestElevatedPermissions = false;