diff --git a/snimpy/basictypes.py b/snimpy/basictypes.py
index c890440..478260c 100644
--- a/snimpy/basictypes.py
+++ b/snimpy/basictypes.py
@@ -439,7 +439,7 @@ def _fromBytes(cls, value, fmt):
                     else:       # format == "d":
                         result += str(number)
                 elif format == "a":
-                    result += bb.decode("ascii")
+                    result += bb.decode("ascii", "ignore")
                 elif format == "t":
                     result += bb.decode("utf-8")
                 else:
@@ -666,6 +666,9 @@ def __str__(self):
         else:
             return str(self._value)
 
+    def __hash__(self):
+        return self._value
+
 
 @ordering_with_cmp
 class Oid(Type):