diff --git a/jpos/src/main/java/org/jpos/iso/ISOUtil.java b/jpos/src/main/java/org/jpos/iso/ISOUtil.java
index d92f9264c7..6ed891322b 100644
--- a/jpos/src/main/java/org/jpos/iso/ISOUtil.java
+++ b/jpos/src/main/java/org/jpos/iso/ISOUtil.java
@@ -299,7 +299,7 @@ public static String bcd2str(byte[] b, int offset,
         return d.toString();
     }
     /**
-     * converts a a byte array to a String with padding support
+     * converts a byte array to a String with padding support
      * @param b - HEX representation
      * @param offset - starting offset
      * @param len - BCD field len
diff --git a/jpos/src/main/java/org/jpos/iso/channel/NACChannel.java b/jpos/src/main/java/org/jpos/iso/channel/NACChannel.java
index 9d9ffd50d0..09f1fd46c1 100644
--- a/jpos/src/main/java/org/jpos/iso/channel/NACChannel.java
+++ b/jpos/src/main/java/org/jpos/iso/channel/NACChannel.java
@@ -114,7 +114,7 @@ protected void sendMessageHeader(ISOMsg m, int len) throws IOException {
      * @param header String as seen by QSP
      */
     public void setHeader (String header) {
-        super.setHeader (ISOUtil.str2bcd(header, false));
+        super.setHeader(ISOUtil.hex2byte(header, null)); //fixes #jPOS-510
     }
     public void setConfiguration (Configuration cfg) 
         throws ConfigurationException
diff --git a/jpos/src/test/java/org/jpos/iso/channel/NACChannelTest.java b/jpos/src/test/java/org/jpos/iso/channel/NACChannelTest.java
index ff4a9aad28..233f24c22c 100644
--- a/jpos/src/test/java/org/jpos/iso/channel/NACChannelTest.java
+++ b/jpos/src/test/java/org/jpos/iso/channel/NACChannelTest.java
@@ -27,9 +27,11 @@
 import static org.junit.jupiter.api.Assertions.fail;
 
 import java.net.ServerSocket;
+import java.nio.charset.StandardCharsets;
 
 import org.jpos.iso.ISOMsg;
 import org.jpos.iso.ISOPackager;
+import org.jpos.iso.ISOUtil;
 import org.jpos.iso.filter.DelayFilter;
 import org.jpos.iso.packager.CTCSubFieldPackager;
 import org.jpos.iso.packager.ISO93APackager;
@@ -236,4 +238,17 @@ public void testSetHeaderThrowsNullPointerException() throws Throwable {
             assertSame(TPDU2, nACChannel.getHeader(), "nACChannel.getHeader()");
         }
     }
+
+    @Test
+    void testSetHeaderDoesNotMangleOnNonHexCharacters() {
+        //jPOS-510
+        String expectedTpdu = "A4M09000";
+        String hex = ISOUtil.hexString(expectedTpdu.getBytes()); //"41344D3039303030"
+
+        NACChannel channel = new NACChannel();
+        channel.setHeader(hex);
+
+        byte[] header = channel.getHeader();
+        assertEquals(expectedTpdu, new String(header, StandardCharsets.UTF_8));
+    }
 }