diff --git a/addons/xterm-addon-attach/src/AttachAddon.ts b/addons/xterm-addon-attach/src/AttachAddon.ts
index 117b2b58..279d1b2e 100644
--- a/addons/xterm-addon-attach/src/AttachAddon.ts
+++ b/addons/xterm-addon-attach/src/AttachAddon.ts
@@ -33,6 +33,7 @@ export class AttachAddon implements ITerminalAddon {
 
     if (this._bidirectional) {
       this._disposables.push(terminal.onData(data => this._sendData(data)));
+      this._disposables.push(terminal.onBinary(data => this._sendBinary(data)));
     }
 
     this._disposables.push(addSocketListener(this._socket, 'close', () => this.dispose()));
@@ -51,6 +52,17 @@ export class AttachAddon implements ITerminalAddon {
     }
     this._socket.send(data);
   }
+
+  private _sendBinary(data: string): void {
+    if (this._socket.readyState !== 1) {
+      return;
+    }
+    const buffer = new Uint8Array(data.length);
+    for (let i = 0; i < data.length; ++i) {
+      buffer[i] = data.charCodeAt(i) & 255;
+    }
+    this._socket.send(buffer);
+  }
 }
 
 function addSocketListener<K extends keyof WebSocketEventMap>(socket: WebSocket, type: K, handler: (this: WebSocket, ev: WebSocketEventMap[K]) => any): IDisposable {
diff --git a/src/Terminal.ts b/src/Terminal.ts
index 3c589ffa..6a039a0e 100644
--- a/src/Terminal.ts
+++ b/src/Terminal.ts
@@ -169,6 +169,8 @@ export class Terminal extends Disposable implements ITerminal, IDisposable, IInp
   public get onCursorMove(): IEvent<void> { return this._onCursorMove.event; }
   private _onData = new EventEmitter<string>();
   public get onData(): IEvent<string> { return this._onData.event; }
+  private _onBinary = new EventEmitter<string>();
+  public get onBinary(): IEvent<string> { return this._onBinary.event; }
   private _onKey = new EventEmitter<{ key: string, domEvent: KeyboardEvent }>();
   public get onKey(): IEvent<{ key: string, domEvent: KeyboardEvent }> { return this._onKey.event; }
   private _onLineFeed = new EventEmitter<void>();
@@ -221,6 +223,7 @@ export class Terminal extends Disposable implements ITerminal, IDisposable, IInp
     this._coreService = this._instantiationService.createInstance(CoreService, () => this.scrollToBottom());
     this._instantiationService.setService(ICoreService, this._coreService);
     this._coreService.onData(e => this._onData.fire(e));
+    this._coreService.onBinary(e => this._onBinary.fire(e));
     this._coreMouseService = this._instantiationService.createInstance(CoreMouseService);
     this._instantiationService.setService(ICoreMouseService, this._coreMouseService);
     this._dirtyRowService = this._instantiationService.createInstance(DirtyRowService);
diff --git a/src/TestUtils.test.ts b/src/TestUtils.test.ts
index e7c48381..84c0d0b7 100644
--- a/src/TestUtils.test.ts
+++ b/src/TestUtils.test.ts
@@ -32,6 +32,7 @@ export class MockTerminal implements ITerminal {
   onLineFeed: IEvent<void>;
   onSelectionChange: IEvent<void>;
   onData: IEvent<string>;
+  onBinary: IEvent<string>;
   onTitleChange: IEvent<string>;
   onScroll: IEvent<number>;
   onKey: IEvent<{ key: string; domEvent: KeyboardEvent; }>;
diff --git a/src/Types.d.ts b/src/Types.d.ts
index 2a922ae1..f4d3a556 100644
--- a/src/Types.d.ts
+++ b/src/Types.d.ts
@@ -180,6 +180,7 @@ export interface IPublicTerminal extends IDisposable {
   markers: IMarker[];
   onCursorMove: IEvent<void>;
   onData: IEvent<string>;
+  onBinary: IEvent<string>;
   onKey: IEvent<{ key: string, domEvent: KeyboardEvent }>;
   onLineFeed: IEvent<void>;
   onScroll: IEvent<number>;
diff --git a/src/common/TestUtils.test.ts b/src/common/TestUtils.test.ts
index 7d9c3aa6..7e47d4b0 100644
--- a/src/common/TestUtils.test.ts
+++ b/src/common/TestUtils.test.ts
@@ -50,8 +50,10 @@ export class MockCoreService implements ICoreService {
   decPrivateModes: IDecPrivateModes = {} as any;
   onData: IEvent<string> = new EventEmitter<string>().event;
   onUserInput: IEvent<void> = new EventEmitter<void>().event;
+  onBinary: IEvent<string> = new EventEmitter<string>().event;
   reset(): void {}
   triggerDataEvent(data: string, wasUserInput?: boolean): void {}
+  triggerBinaryEvent(data: string): void {}
 }
 
 export class MockDirtyRowService implements IDirtyRowService {
diff --git a/src/common/Types.d.ts b/src/common/Types.d.ts
index 2f742038..2dcc704b 100644
--- a/src/common/Types.d.ts
+++ b/src/common/Types.d.ts
@@ -249,5 +249,8 @@ export interface ICoreMouseProtocol {
  * The tracking encoding can be registered and activated at the CoreMouseService.
  * If a ICoreMouseEvent passes all procotol restrictions it will be encoded
  * with the active encoding and sent out.
+ * Note: Returning an empty string will supress sending a mouse report,
+ * which can be used to skip creating falsey reports in limited encodings
+ * (DEFAULT only supports up to 223 1-based as coord value).
  */
 export type CoreMouseEncoding = (event: ICoreMouseEvent) => string;
diff --git a/src/common/services/CoreMouseService.test.ts b/src/common/services/CoreMouseService.test.ts
index f7d3bf83..2bf011b0 100644
--- a/src/common/services/CoreMouseService.test.ts
+++ b/src/common/services/CoreMouseService.test.ts
@@ -79,6 +79,7 @@ describe('CoreMouseService', () => {
       cms = new CoreMouseService(bufferService, coreService);
       reports = [];
       coreService.triggerDataEvent = (data: string, userInput?: boolean) => reports.push(data);
+      coreService.triggerBinaryEvent = (data: string) => reports.push(data);
     });
     it('NONE', () => {
       assert.equal(cms.triggerMouseEvent({ col: 0, row: 0, button: CoreMouseButton.LEFT, action: CoreMouseAction.DOWN }), false);
@@ -143,11 +144,11 @@ describe('CoreMouseService', () => {
         cms.activeProtocol = 'ANY';
         for (let i = 0; i < bufferService.cols; ++i) {
           assert.equal(cms.triggerMouseEvent({ col: i, row: 0, button: CoreMouseButton.LEFT, action: CoreMouseAction.DOWN }), true);
-          // capped at 95
-          if (i < 95) {
-            assert.deepEqual(toBytes(reports.pop()), [0x1b, 0x5b, 0x4d, 0x20, i + 33, 0x21]);
+          if (i > 222) {
+            // supress mouse reports if we are out of addressible range (max. 222)
+            assert.deepEqual(toBytes(reports.pop()), []);
           } else {
-            assert.deepEqual(toBytes(reports.pop()), [0x1b, 0x5b, 0x4d, 0x20, 0x7f, 0x21]);
+            assert.deepEqual(toBytes(reports.pop()), [0x1b, 0x5b, 0x4d, 0x20, i + 33, 0x21]);
           }
         }
       });
diff --git a/src/common/services/CoreMouseService.ts b/src/common/services/CoreMouseService.ts
index 500655b9..0bd25dd0 100644
--- a/src/common/services/CoreMouseService.ts
+++ b/src/common/services/CoreMouseService.ts
@@ -121,15 +121,17 @@ const DEFAULT_ENCODINGS: {[key: string]: CoreMouseEncoding} = {
   /**
    * DEFAULT - CSI M Pb Px Py
    * Single byte encoding for coords and event code.
-   * Can encode values up to 223. The Encoding of higher
-   * values is not UTF-8 compatible (and currently limited
-   * to 95 in xterm.js).
+   * Can encode values up to 223 (1-based).
    */
   DEFAULT: (e: ICoreMouseEvent) => {
-    let params = [eventCode(e, false) + 32, e.col + 32, e.row + 32];
-    // FIXME: we are currently limited to ASCII range
-    params = params.map(v => (v > 127) ? 127 : v);
-    // FIXED: params = params.map(v => (v > 255) ? 0 : value);
+    const params = [eventCode(e, false) + 32, e.col + 32, e.row + 32];
+    // supress mouse report if we exceed addressible range
+    // Note this is handled differently by emulators
+    // - xterm:         sends 0;0 coords instead
+    // - vte, konsole:  no report
+    if (params[0] > 255 || params[1] > 255 || params[2] > 255) {
+      return '';
+    }
     return `\x1b[M${S(params[0])}${S(params[1])}${S(params[2])}`;
   },
   /**
@@ -266,7 +268,14 @@ export class CoreMouseService implements ICoreMouseService {
 
     // encode report and send
     const report = this._encodings[this._activeEncoding](e);
-    this._coreService.triggerDataEvent(report, true);
+    if (report) {
+      // always send DEFAULT as binary data
+      if (this._activeEncoding === 'DEFAULT') {
+        this._coreService.triggerBinaryEvent(report);
+      } else {
+        this._coreService.triggerDataEvent(report, true);
+      }
+    }
 
     this._lastEvent = e;
 
diff --git a/src/common/services/CoreService.ts b/src/common/services/CoreService.ts
index 11c3f305..35b61e84 100644
--- a/src/common/services/CoreService.ts
+++ b/src/common/services/CoreService.ts
@@ -23,6 +23,8 @@ export class CoreService implements ICoreService {
   public get onData(): IEvent<string> { return this._onData.event; }
   private _onUserInput = new EventEmitter<void>();
   public get onUserInput(): IEvent<void> { return this._onUserInput.event; }
+  private _onBinary = new EventEmitter<string>();
+  public get onBinary(): IEvent<string> { return this._onBinary.event; }
 
   constructor(
     // TODO: Move this into a service
@@ -59,4 +61,12 @@ export class CoreService implements ICoreService {
     this._logService.debug(`sending data "${data}"`, () => data.split('').map(e => e.charCodeAt(0)));
     this._onData.fire(data);
   }
+
+  public triggerBinaryEvent(data: string): void {
+    if (this._optionsService.options.disableStdin) {
+      return;
+    }
+    this._logService.debug(`sending binary "${data}"`, () => data.split('').map(e => e.charCodeAt(0)));
+    this._onBinary.fire(data);
+  }
 }
diff --git a/src/common/services/Services.ts b/src/common/services/Services.ts
index e4ff90d0..45d39a6a 100644
--- a/src/common/services/Services.ts
+++ b/src/common/services/Services.ts
@@ -68,6 +68,7 @@ export interface ICoreService {
 
   readonly onData: IEvent<string>;
   readonly onUserInput: IEvent<void>;
+  readonly onBinary: IEvent<string>;
 
   reset(): void;
 
@@ -78,8 +79,14 @@ export interface ICoreService {
    * resulting from parsing incoming data). When true this will also:
    * - Scroll to the bottom of the buffer.s
    * - Fire the `onUserInput` event (so selection can be cleared).
-    */
+   */
   triggerDataEvent(data: string, wasUserInput?: boolean): void;
+
+  /**
+   * Triggers the onBinary event in the public API.
+   * @param data The data that is being emitted.
+   */
+   triggerBinaryEvent(data: string): void;
 }
 
 export const IDirtyRowService = createDecorator<IDirtyRowService>('DirtyRowService');
diff --git a/src/public/Terminal.ts b/src/public/Terminal.ts
index c167bed8..397898c7 100644
--- a/src/public/Terminal.ts
+++ b/src/public/Terminal.ts
@@ -27,6 +27,7 @@ export class Terminal implements ITerminalApi {
   public get onLineFeed(): IEvent<void> { return this._core.onLineFeed; }
   public get onSelectionChange(): IEvent<void> { return this._core.onSelectionChange; }
   public get onData(): IEvent<string> { return this._core.onData; }
+  public get onBinary(): IEvent<string> { return this._core.onBinary; }
   public get onTitleChange(): IEvent<string> { return this._core.onTitleChange; }
   public get onScroll(): IEvent<number> { return this._core.onScroll; }
   public get onKey(): IEvent<{ key: string, domEvent: KeyboardEvent }> { return this._core.onKey; }
diff --git a/test/api/MouseTracking.api.ts b/test/api/MouseTracking.api.ts
index f8124350..7cae660f 100644
--- a/test/api/MouseTracking.api.ts
+++ b/test/api/MouseTracking.api.ts
@@ -220,6 +220,7 @@ describe('Mouse Tracking Tests', () => {
     await page.evaluate(`
       window.calls = [];
       window.term.onData(e => calls.push( Array.from(e).map(el => el.charCodeAt(0)) ));
+      window.term.onBinary(e => calls.push( Array.from(e).map(el => el.charCodeAt(0)) ));
       window.term.setOption('fontSize', ${fontSize});
       window.term.resize(${cols}, ${rows});
     `);
@@ -255,12 +256,17 @@ describe('Mouse Tracking Tests', () => {
       await pollFor(page, () => getReports(encoding), [{col: 51, row: 11, state: {action: 'press', button: 'left', modifier: {control: false, shift: false, meta: false}}}]);
 
       // test at max rows/cols
-      // bug: we are capped at col 95 currently
-      // fix: allow values up to 223, any bigger should drop to 0
-      await mouseMove(cols - 1, rows - 1);
+      // capped at 223 (1-based)
+      await mouseMove(223 - 1, rows - 1);
       await mouseDown('left');
       await mouseUp('left');
-      await pollFor(page, () => getReports(encoding), [{col: 95, row: rows, state: {action: 'press', button: 'left', modifier: {control: false, shift: false, meta: false}}}]);
+      await pollFor(page, () => getReports(encoding), [{col: 223, row: rows, state: {action: 'press', button: 'left', modifier: {control: false, shift: false, meta: false}}}]);
+
+      // higher than 223 should not report at all
+      await mouseMove(257, rows - 1);
+      await mouseDown('left');
+      await mouseUp('left');
+      await pollFor(page, () => getReports(encoding), []);
 
       // button press/move/release tests
       // left button
@@ -511,14 +517,13 @@ describe('Mouse Tracking Tests', () => {
       ]);
 
       // test at max rows/cols
-      // bug: we are capped at col 95 currently
-      // fix: allow values up to 223, any bigger should drop to 0
-      await mouseMove(cols - 1, rows - 1);
+      // capped at 223 (1-based)
+      await mouseMove(223 - 1, rows - 1);
       await mouseDown('left');
       await mouseUp('left');
       await pollFor(page, () => getReports(encoding), [
-        {col: 95, row: rows, state: {action: 'press', button: 'left', modifier: {control: false, shift: false, meta: false}}},
-        {col: 95, row: rows, state: {action: 'release', button: '<none>', modifier: {control: false, shift: false, meta: false}}}
+        {col: 223, row: rows, state: {action: 'press', button: 'left', modifier: {control: false, shift: false, meta: false}}},
+        {col: 223, row: rows, state: {action: 'release', button: '<none>', modifier: {control: false, shift: false, meta: false}}}
       ]);
 
       // button press/move/release tests
@@ -821,14 +826,13 @@ describe('Mouse Tracking Tests', () => {
       ]);
 
       // test at max rows/cols
-      // bug: we are capped at col 95 currently
-      // fix: allow values up to 223, any bigger should drop to 0
-      await mouseMove(cols - 1, rows - 1);
+      // capped at 223 (1-based)
+      await mouseMove(223 - 1, rows - 1);
       await mouseDown('left');
       await mouseUp('left');
       await pollFor(page, () => getReports(encoding), [
-        {col: 95, row: rows, state: {action: 'press', button: 'left', modifier: {control: false, shift: false, meta: false}}},
-        {col: 95, row: rows, state: {action: 'release', button: '<none>', modifier: {control: false, shift: false, meta: false}}}
+        {col: 223, row: rows, state: {action: 'press', button: 'left', modifier: {control: false, shift: false, meta: false}}},
+        {col: 223, row: rows, state: {action: 'release', button: '<none>', modifier: {control: false, shift: false, meta: false}}}
       ]);
 
       // button press/move/release tests
@@ -1142,15 +1146,14 @@ describe('Mouse Tracking Tests', () => {
       ]);
 
       // test at max rows/cols
-      // bug: we are capped at col 95 currently
-      // fix: allow values up to 223, any bigger should drop to 0
-      await mouseMove(cols - 1, rows - 1);
+      // capped at 223 (1-based)
+      await mouseMove(223 - 1, rows - 1);
       await mouseDown('left');
       await mouseUp('left');
       await pollFor(page, () => getReports(encoding), [
-        {col: 95, row: rows, state: {action: 'move', button: '<none>', modifier: {control: false, shift: false, meta: false}}},
-        {col: 95, row: rows, state: {action: 'press', button: 'left', modifier: {control: false, shift: false, meta: false}}},
-        {col: 95, row: rows, state: {action: 'release', button: '<none>', modifier: {control: false, shift: false, meta: false}}}
+        {col: 223, row: rows, state: {action: 'move', button: '<none>', modifier: {control: false, shift: false, meta: false}}},
+        {col: 223, row: rows, state: {action: 'press', button: 'left', modifier: {control: false, shift: false, meta: false}}},
+        {col: 223, row: rows, state: {action: 'release', button: '<none>', modifier: {control: false, shift: false, meta: false}}}
       ]);
 
       // button press/move/release tests
diff --git a/typings/xterm.d.ts b/typings/xterm.d.ts
index 9728a72c..a086d030 100644
--- a/typings/xterm.d.ts
+++ b/typings/xterm.d.ts
@@ -421,6 +421,17 @@ declare module 'xterm' {
      */
     constructor(options?: ITerminalOptions);
 
+    /**
+     * Adds an event listener for when a binary event fires. This is used to
+     * enable non UTF-8 conformant binary messages to be sent to the backend.
+     * Currently this is only used for a certain type of mouse reports that
+     * happen to be not UTF-8 compatible.
+     * The event value is a JS string, pass it to the underlying pty as
+     * binary data, e.g. `pty.write(Buffer.from(data, 'binary'))`. 
+     * @returns an `IDisposable` to stop listening.
+     */
+    onBinary: IEvent<string>;
+
     /**
      * Adds an event listener for the cursor moves.
      * @returns an `IDisposable` to stop listening.