diff --git a/src/main/java/com/solab/iso8583/CustomBinaryField.java b/src/main/java/com/solab/iso8583/CustomBinaryField.java
new file mode 100644
index 0000000..594b89b
--- /dev/null
+++ b/src/main/java/com/solab/iso8583/CustomBinaryField.java
@@ -0,0 +1,17 @@
+package com.solab.iso8583;
+
+/**
+ * An extension of the CustomField interface, useful for binary fields.
+ * CustomBinaryField encoders can return null for the two CustomField
+ * methods IF they are only used with binary messages.
+ *
+ * @author Enrique Zamudio
+ *         Date: 07/05/13 13:04
+ */
+public interface CustomBinaryField<T> extends CustomField<T> {
+
+    public T decodeBinaryField(byte[] value, int offset, int length);
+
+   	public byte[] encodeBinaryField(T value);
+
+}