diff --git a/ChangeLog b/ChangeLog
index bd9d169..dc291dd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -3,6 +3,8 @@
 	* EcCommand.m: Simplify handling of loss of process and configuration
 	error alarms.  Clear such alarms when we receive a ping from the
 	process.
+	EcLogger.[hm]: Add documentation in the header, plus a new method to
+	make subclassing a bit easier.  Fix bug in naming of config keys.
 
 2014-09-04  Richard Frith-Macdonald <rfm@gnu.org>
 
diff --git a/EcLogger.h b/EcLogger.h
index 0ad8606..2b63a07 100644
--- a/EcLogger.h
+++ b/EcLogger.h
@@ -30,6 +30,24 @@
 #ifndef	_ECLOGGER_H
 #define	_ECLOGGER_H
 
+/** Instances of the EcLogger class are used to handle various types of
+ * logging.<br />
+ * The default implementation supports writing to local files and sending
+ * logs to a remote process (by default, the Command server).<br />
+ * Configuration options control the amount of data buffered in memory
+ * before logs are flushed, and the amount of time for which data may
+ * be buffered in memory before being flushed.<br />
+ * Configuration options are ???Server (to specify the name of the
+ * server to log to if not Command) and ???Flush (to specify when to
+ * flush the in-memory buffer), where ??? is the type of logging being
+ * done by a logger object.<br />
+ * When there is no type-specific flush configuration, the DefaultFlush
+ * configuration key will be used.<br />
+ * The flush configuration value must be a floating point number of
+ * seconds after which to flush, optionally folowed by a colon and an
+ * integer number of kilobytes of data allowed before the buffer is
+ * flushed.
+ */
 @interface	EcLogger : NSObject <CmdPing>
 {
   NSRecursiveLock       *lock;
@@ -48,17 +66,50 @@
   BOOL			registered;
   BOOL			pendingFlush;
 }
+
+/** Returns a (cached) logger object for the specified type of logging.<br />
+ * Creates a new object (adding it to the cache) if none exists.
+ */
 + (EcLogger*) loggerForType: (EcLogType)t;
+
+/** Sets the factory class used by the +loggerForType: method
+ * to create new EcLogger objects.<br />
+ * This is provided as a convenience so that you can get all code to use
+ * a subclass of EcLogger without having to use a category to override
+ * that method.
+ */
++ (void) setFactory: (Class)c;
+
+/** Supports the CmdPing protocol.
+ */
 - (void) cmdGnip: (id <CmdPing>)from
 	sequence: (unsigned)num
 	   extra: (NSData*)data;
+
 - (void) cmdMadeConnectionToServer: (NSString*)name;
+
+/** Supports the CmdPing protocol.
+ */
 - (void) cmdPing: (id <CmdPing>)from
 	sequence: (unsigned)num
 	   extra: (NSData*)data;
+
+/** Called to flush accumulated data from the message instance variable.<br />
+ * On return from this method the variable should be empty.
+ */
 - (void) flush;
+
+/** Called to log a message by appending to the message instance variable.
+ * This method may also schedule an asynchronous flush if the message
+ * buffer is too large or if the last flush was too long ago.
+ */
 - (void) log: (NSString*)fmt arguments: (va_list)args;
+
+/** Called when the user defaults system has changed and a configuration
+ * update may have occurred.
+ */
 - (void) update;
+
 @end
 
 #endif
diff --git a/EcLogger.m b/EcLogger.m
index e3a54cf..cf6d350 100644
--- a/EcLogger.m
+++ b/EcLogger.m
@@ -35,6 +35,7 @@
 
 @implementation	EcLogger
 
+static Class            loggersClass;
 static NSLock           *loggersLock;
 static NSMutableArray	*loggers;
 static NSArray          *modes;
@@ -49,6 +50,7 @@ static NSArray          *modes;
       loggers = [[NSMutableArray alloc] initWithCapacity: 6];
       objects[0] = NSDefaultRunLoopMode;
       modes = [[NSArray alloc] initWithObjects: objects count: 1];
+      [self setFactory: self];
     }
 }
 
@@ -69,16 +71,16 @@ static NSArray          *modes;
 	  return logger;
 	}
     }
-  logger = [[EcLogger alloc] init];
+  logger = [[loggersClass alloc] init];
   if (logger != nil)
     {
       logger->lock = [NSRecursiveLock new];
       logger->type = t;
       logger->key = [cmdLogKey(t) copy];
       logger->flushKey
-	= [[NSString alloc] initWithFormat: @"BS%@Flush", logger->key];
+	= [[NSString alloc] initWithFormat: @"%@Flush", logger->key];
       logger->serverKey
-	= [[NSString alloc] initWithFormat: @"BS%@Server", logger->key];
+	= [[NSString alloc] initWithFormat: @"%@Server", logger->key];
       logger->interval = 10.0;
       logger->size = 8 * 1024;
       logger->message = [[NSMutableString alloc] initWithCapacity: 2048];
@@ -96,6 +98,15 @@ static NSArray          *modes;
   return logger;
 }
 
++ (void) setFactory: (Class)c
+{
+  if (Nil == c) c = [self class];
+  NSAssert([c isSubclassOfClass: self], NSInvalidArgumentException);
+  [loggersLock lock];
+  loggersClass = c;
+  [loggersLock unlock];
+}
+
 /* Should only be called on main thread, but doesn't matter.
  */
 - (void) cmdGnip: (id <CmdPing>)from
@@ -530,7 +541,7 @@ static NSArray          *modes;
   str = [defs stringForKey: flushKey];
   if (str == nil)
     {
-      str = [defs stringForKey: @"BSDefaultFlush"];	// Default settings.
+      str = [defs stringForKey: @"DefaultFlush"];	// Default settings.
     }
   if (str != nil)
     {