diff --git a/birdy-slim-iot/payload-formatters/testing.js b/birdy-slim-iot/payload-formatters/testing.js
new file mode 100644
index 0000000..3e5c766
--- /dev/null
+++ b/birdy-slim-iot/payload-formatters/testing.js
@@ -0,0 +1,35 @@
+function Decoder(bytes, port) {
+  var data = {}
+  function bytesToString(a) {
+    return a.map(function(x){ return String.fromCharCode(x) }).join('') // because very OLD js parser
+  }
+  switch (port) {
+    case 1: // Technical Received Acknowledgment '|5||C|''
+      // 31 32 33 34 35 20
+      data.type = 'ack'
+      data.ack = 'recv'
+      data.msgid = bytesToString(bytes.splice(0,5))
+      data.rssi = bytes.splice(0,1) * 1
+      break;
+    case 2: // Read and Operational Acknowledgment 'AA|5|' and Operational '33|5|<CustomByte(s)>'
+      // AA 31 32 33 34 35
+      // operational ack with Payload "test"(maybe you should use a single byte)
+      // 33 31 32 33 34 35 54 65 73 74
+      data.type = 'ack'
+      data.ack = bytes.splice(0,1) == 0xAA ? 'read' : 'operational'
+      data.msgid = bytesToString(bytes.splice(0,5))
+      if (data.ack === 'operational') {
+        data.operationalData = bytesToString(bytes)
+      }
+      break;
+    case 5:  // GPS Tracking Port
+      data.type = 'gps'
+      data.latitude = ((bytes[0]<<24)>>>0) + ((bytes[1]<<16)>>>0) + ((bytes[2]<<8)>>>0) + bytes[3]
+      data.latitude /= 10e4
+      data.longitude = ((bytes[4]<<24)>>>0) + ((bytes[5]<<16)>>>0) + ((bytes[6]<<8)>>>0) + bytes[7]
+      data.longitude /= 10e4
+      data.lastGPSAcquisition = bytes[8]
+      break;
+  }
+  return data;
+}