diff --git a/jsmpp/src/main/java/org/jsmpp/bean/OptionalParameter.java b/jsmpp/src/main/java/org/jsmpp/bean/OptionalParameter.java
index 2c3aca5..faa2f60 100644
--- a/jsmpp/src/main/java/org/jsmpp/bean/OptionalParameter.java
+++ b/jsmpp/src/main/java/org/jsmpp/bean/OptionalParameter.java
@@ -305,7 +305,7 @@ public static Tag valueOf(short code) {
                 if (tag.code == code)
                     return tag;
             }
-            throw new IllegalArgumentException("No tag for: " + code);
+            return null;
         }
     }
     
diff --git a/jsmpp/src/main/java/org/jsmpp/bean/OptionalParameters.java b/jsmpp/src/main/java/org/jsmpp/bean/OptionalParameters.java
index 411b95d..5f1cf94 100644
--- a/jsmpp/src/main/java/org/jsmpp/bean/OptionalParameters.java
+++ b/jsmpp/src/main/java/org/jsmpp/bean/OptionalParameters.java
@@ -100,10 +100,8 @@ public static OptionalParameter.Byte newSarTotalSegments(int value) {
      * @return the OptionalParameter object.
      */
     public static OptionalParameter deserialize(short tagCode, byte[] content) {
-        Tag tag = null;
-        try {
-            tag = Tag.valueOf(tagCode);
-        } catch (IllegalArgumentException e) {
+        Tag tag = Tag.valueOf(tagCode);
+        if(tag == null) {
             return new COctetString(tagCode, content);
         }
         
diff --git a/jsmpp/src/test/java/org/jsmpp/bean/OptionalParameterTest.java b/jsmpp/src/test/java/org/jsmpp/bean/OptionalParameterTest.java
index 04f9c47..b483a9c 100644
--- a/jsmpp/src/test/java/org/jsmpp/bean/OptionalParameterTest.java
+++ b/jsmpp/src/test/java/org/jsmpp/bean/OptionalParameterTest.java
@@ -16,7 +16,7 @@
 
 import static org.testng.Assert.assertEquals;
 import static org.testng.Assert.assertTrue;
-import static org.testng.Assert.fail;
+import static org.testng.Assert.assertNull;
 
 import org.jsmpp.bean.OptionalParameter.OctetString;
 import org.jsmpp.bean.OptionalParameter.Tag;
@@ -53,23 +53,13 @@ public void stringParameterDeserialization() {
     @Test
     public void undefinedTag() {
         final short tagCode = 0x0000;
-        try {
-            Tag.valueOf(tagCode);
-            fail("Tag code 0x0000 should be not found");
-        } catch (IllegalArgumentException e) {
-        }
-        OptionalParameters.deserialize(tagCode, "Undefined tag".getBytes());
+        assertNull(Tag.valueOf(tagCode));
     }
     
     @Test
     public void anotherUndefinedTag() {
         short tagCode = (short)(-127 & 0xffff);
-        try {
-            Tag.valueOf(tagCode);
-            fail("Tag code " + tagCode + " should be not found");
-        } catch (IllegalArgumentException e) {
-        }
-        OptionalParameters.deserialize(tagCode, "Undefined tag".getBytes());
+        assertNull(Tag.valueOf(tagCode));
     }
     
     @Test