diff --git a/lib/service_type.js b/lib/service_type.js
index bc726217..c485e76a 100644
--- a/lib/service_type.js
+++ b/lib/service_type.js
@@ -151,13 +151,13 @@ function isProtocol(str) {
 function _u(str) { return "_" + str; }
 function _uu(str) { return str[0] === '_' ? str.substr(1) : str; }
 
-var charset_regex = /[^-a-zA-Z0-9]/;
+var charset_regex = /[^-_a-zA-Z0-9]/;
 function checkLengthAndCharset(str) {
   if (str.length === 0) {
     throw new Error('type ' + str + ' must not be empty');
   }
-  if (str.length > 15) {
-    throw new Error('type ' + str + ' has more than 15 characters');
+  if (str.length > 20) { // Note: this is not according to spec (https://github.com/agnat/node_mdns/issues/264)
+    throw new Error('type ' + str + ' has more than 20 characters');
   }
   if (str.match(charset_regex)) {
     throw new Error('type ' + str + ' may only contain alphanumeric ' +
@@ -170,8 +170,9 @@ function checkFormat(str) {
   if (str.length === 0) {
     throw new Error('type string must not be empty');
   }
-  if (str.length > 16) { // 16 is correct because we have a leading underscore
-    throw new Error('type ' + _uu(str) + ' has more than 15 characters');
+  // 21 is correct because we have a leading underscore
+  if (str.length > 21) { // Note: this is not according to spec (https://github.com/agnat/node_mdns/issues/264)
+    throw new Error('type ' + _uu(str) + ' has more than 20 characters');
   }
   if ( ! str.match(format_regex)) {
     throw new Error('type ' + str + ' must start with an underscore ' +
diff --git a/test.js b/test.js
new file mode 100644
index 00000000..7946a257
--- /dev/null
+++ b/test.js
@@ -0,0 +1,24 @@
+// import the module
+const mdns = require('./');
+
+// advertise a http server on port 4321
+// const ad = mdns.createAdvertisement(mdns.tcp('http'), 4321);
+// ad.start();
+
+// watch all http servers
+const browser = mdns.createBrowser(
+    new mdns.ServiceType({
+        name: 'androidtvremote2',
+        protocol: 'tcp',
+    }),
+);
+browser.on('serviceUp', service => {
+  console.log("service up: ", service);
+});
+browser.on('serviceDown', service => {
+  console.log("service down: ", service);
+});
+browser.start();
+
+// discover all available service types
+const all_the_types = mdns.browseThemAll(); // all_the_types is just another browser...