diff --git a/gex/Unit.py b/gex/Unit.py
index 19a0087..5208254 100644
--- a/gex/Unit.py
+++ b/gex/Unit.py
@@ -1,11 +1,14 @@
 from gex import Client
 
 class Unit:
-    def __init__(self, client :Client, name :str, type :str):
+    def __init__(self, client :Client, name :str):
         self.client = client
         self.unit_name = name
-        self.unit_type = type
-        self.callsign = client.get_callsign(name, type)
+        self.unit_type = self._type()
+        self.callsign = client.get_callsign(name, self.unit_type)
+
+    def _type(self):
+        raise NotImplementedError("Missing _type() in Unit class \"%s\"" % self.__class__.__name__)
 
     def send(self, cmd, pld=None, id=None):
         """ Send a command to the unit """
diff --git a/gex/units/Pin.py b/gex/units/Pin.py
index 7f9bca2..6c372a6 100644
--- a/gex/units/Pin.py
+++ b/gex/units/Pin.py
@@ -1,8 +1,8 @@
 import gex
 
 class Pin(gex.Unit):
-    def __init__(self, client, name):
-        super().__init__(client, name, 'PIN')
+    def _type(self):
+        return 'PIN'
 
     def off(self):
         self.send(0x00)
diff --git a/main.py b/main.py
index f31052b..da235c4 100644
--- a/main.py
+++ b/main.py
@@ -4,8 +4,9 @@ import gex
 
 client = gex.Client()
 
-s = client.ini_read()
-client.ini_write(s)
+if False:
+    s = client.ini_read()
+    client.ini_write(s)
 
 if False:
     buf = client.bulk_read(None, gex.MSG_INI_READ)
@@ -13,7 +14,7 @@ if False:
 
     client.bulk_write(None, gex.MSG_INI_WRITE, buf)
 
-if False:
+if True:
     led = gex.Pin(client, 'LED')
 
     for i in range(0,10):