diff --git a/src/index.js b/src/index.js
index 4ab9005..e79d74c 100644
--- a/src/index.js
+++ b/src/index.js
@@ -634,6 +634,30 @@ const parse = (raw) => {
   return result;
 };
 
+const isTz = (raw) => {
+  let result = false;
+  if (patterns.avl05.test(raw.toString())) {
+    result = true;
+  } else if (patterns.avl08.test(raw.toString())) {
+    result = true;
+  } else if (patterns.avl201.test(raw.toString())) {
+    result = true;
+  } else if (patterns.receiveOk.test(raw.toString())) {
+    result = true;
+  } else if (patterns.picture.test(raw.toString())) {
+    result = true;
+  } else if (patterns.receiveErr.test(raw.toString())) {
+    result = true;
+  } else if (patterns.info.test(raw.toString())) {
+    result = true;
+  } else if (patterns.firmware.test(raw.toString())) {
+    result = true;
+  } else if (patterns.map.test(raw.toString())) {
+    result = true;
+  }
+  return result;
+};
+
 module.exports = {
   parse: parse,
   patterns: patterns,
@@ -647,5 +671,6 @@ module.exports = {
   getCommandInfo: getCommandInfo,
   getCommandMap: getCommandMap,
   verifyLen: verifyLen,
-  verifyCrc: verifyCrc
+  verifyCrc: verifyCrc,
+  isTz: isTz
 };
diff --git a/test/test.js b/test/test.js
index a4b7590..98be530 100644
--- a/test/test.js
+++ b/test/test.js
@@ -678,4 +678,10 @@ describe('tz-parzer', () => {
       data: 'FFD8FFDB008400100B0C0E0C0A100E0D0E1211101318281A181616183123251D283A333D3C3933383740485C4E404457453738506D51575F626768673E4D71797064785C656763011112121815182F1A1A2F634238426363636363636363636363636363'
     }]);
   });
+
+  it('should return true', () => {
+    const raw = new Buffer('$$B6869444005480041|AA$GPRMC,194329.000,A,3321.6735,S,07030.7640,W,0.00,0.00,090216,,,A*6C|02.1|01.3|01.7|000000000000|20160209194326|13981188|00000000|32D3A03F|0000|0.6376|0100|995F\r\n');
+    const data = tz.isTz(raw);
+    expect(data).to.be.a.true;
+  });
 });