diff --git a/README.md b/README.md
index 6ac36320..9c0fbfe9 100644
--- a/README.md
+++ b/README.md
@@ -11,7 +11,10 @@ Just upload the default firmata sketch into your Arduino and you are all set.
 pyFirmata2 is an updated version of pyFirmata which *replaces loops
 with callbacks*. Instead of unreliable "sleep" commands in a loop the
 Python application registers callbacks which are then called
-every time after new data has arrived.
+every time after new data has arrived. This means for the analogue
+channels the callbacks are called at the specified sampling rate
+while the the digital ports call the callback functions after
+a state change has happened (from 0 to 1 or 1 to 0).
 
 This API has been used in the Digital Signal Processing (DSP) class to
 practise realtime filtering of analogue sensor
@@ -138,13 +141,12 @@ number, and the mode:
   - 'o' for output
   - 'p' for pwm
   - 's' for servo.
-All seperated by `:`. Eg. `a:0:i` for analog 0 as input or `d:3:p` for
-digital pin 3 as pwm:
+All seperated by `:`, for example:
 ```
-    analog_0 = board.get_pin('a:0:i')
-    analog_0.read()
-    pin3 = board.get_pin('d:3:p')
-    pin3.write(0.6)
+    digital_0 = board.get_pin('d:0:i')
+    v = digital_0.read()
+    pin3 = board.get_pin('d:3:o')
+    pin3.write(True)
 ```	
 	
 ### Closing the board
diff --git a/examples/README.md b/examples/README.md
index a415c1e2..56939901 100644
--- a/examples/README.md
+++ b/examples/README.md
@@ -5,4 +5,4 @@
   - Realtime oscilloscope. This script shows how to process data at a given sampling rate.
   - Printing data on the screen using an event handler
   - Digital in reads from a digital pin using an event handler
-  - Flashing LED using a loop
+  - Flashing LED using a timer
diff --git a/examples/realtime_two_channel_scope.py b/examples/realtime_two_channel_scope.py
index a5233c58..5ead21e4 100755
--- a/examples/realtime_two_channel_scope.py
+++ b/examples/realtime_two_channel_scope.py
@@ -58,17 +58,18 @@ def addData(self,d):
 
 # called for every new sample at channel 0 which has arrived from the Arduino
 # "data" contains the new sample
-def callBack(data):
+def callBack1(data):
     # filter your channel 0 samples here:
     # data = self.filter_of_channel0.dofilter(data)
     # send the sample to the plotwindow
     qtPanningPlot1.addData(data)
-    ch1 = board.analog[1].read()
-    # 1st sample of 2nd channel might arrive later so need to check
-    if ch1:
-        # filter your channel 1 samples here:
-        # ch1 = self.filter_of_channel1.dofilter(ch1)
-        qtPanningPlot2.addData(ch1)
+
+def callBack2(data):
+    # filter your channel 0 samples here:
+    # data = self.filter_of_channel0.dofilter(data)
+    # send the sample to the plotwindow
+    qtPanningPlot2.addData(data)
+
 
 # Get the Ardunio board.
 board = Arduino(PORT)
@@ -79,7 +80,8 @@ def callBack(data):
 # Register the callback which adds the data to the animated plot
 # The function "callback" (see above) is called when data has
 # arrived on channel 0.
-board.analog[0].register_callback(callBack)
+board.analog[0].register_callback(callBack1)
+board.analog[1].register_callback(callBack2)
 
 # Enable the callback
 board.analog[0].enable_reporting()