diff --git a/demo/client.ts b/demo/client.ts
index a3a912f6..a38b8a5c 100644
--- a/demo/client.ts
+++ b/demo/client.ts
@@ -134,6 +134,7 @@ function createTerminal(): void {
         pid = processId;
         socketURL += processId;
         socket = new WebSocket(socketURL);
+        socket.binaryType = 'arraybuffer';
         socket.onopen = runRealTerminal;
         socket.onclose = runFakeTerminal;
         socket.onerror = runFakeTerminal;
diff --git a/demo/server.js b/demo/server.js
index 5ff9ca61..86bc9069 100644
--- a/demo/server.js
+++ b/demo/server.js
@@ -32,7 +32,8 @@ function startServer() {
           cols: cols || 80,
           rows: rows || 24,
           cwd: process.env.PWD,
-          env: process.env
+          env: process.env,
+          encoding: null
         });
 
     console.log('Created terminal with PID: ' + term.pid);
@@ -62,20 +63,20 @@ function startServer() {
     ws.send(logs[term.pid]);
 
     function buffer(socket, timeout) {
-      let s = '';
+      let buffer = [];
       let sender = null;
       return (data) => {
-        s += data;
+        buffer.push(data);
         if (!sender) {
           sender = setTimeout(() => {
-            socket.send(s);
-            s = '';
+            socket.send(Buffer.concat(buffer));
+            buffer = [];
             sender = null;
           }, timeout);
         }
       };
     }
-    const send = buffer(ws, 5);
+  const send = buffer(ws, 5);
 
     term.on('data', function(data) {
       try {
diff --git a/src/addons/attach/attach.ts b/src/addons/attach/attach.ts
index f121e2e2..7333f92b 100644
--- a/src/addons/attach/attach.ts
+++ b/src/addons/attach/attach.ts
@@ -42,6 +42,11 @@ export function attach(term: Terminal, socket: WebSocket, bidirectional: boolean
   addonTerminal.__getMessage = function(ev: MessageEvent): void {
     let str: string;
 
+    if (ev.data instanceof ArrayBuffer) {
+      addonTerminal.writeUtf8(new Uint8Array(ev.data));
+      return;
+    }
+
     if (typeof ev.data === 'object') {
       if (!myTextDecoder) {
         myTextDecoder = new TextDecoder();