diff --git a/README.md b/README.md
index c96d6de..614e822 100644
--- a/README.md
+++ b/README.md
@@ -34,7 +34,7 @@ Both the parent window and iFrame must load COMB.
 <script type="text/javascript" src="./holo_hosting_comb.js"></script>
 <script type="text/javascript">
 (async () => {
-    const child = await comb.connect( url );
+    const child = await comb.connect( url, 5000, signal => console.log('comb got signal', signal) );
 
     await child.set("development_mode", true );
     await child.set("welcome_greeting", "Hello" );
diff --git a/html/chaperone/index.html b/html/chaperone/index.html
index c30580d..7f70bad 100644
--- a/html/chaperone/index.html
+++ b/html/chaperone/index.html
@@ -1,35 +1,37 @@
-
 <script src="/comb/holo_hosting_comb.js"></script>
 
 <h1>Chaperone!</h1>
 
 <script type="text/javascript">
-    (async function () {
+  (async function () {
 
-	function HolochainTestError(message) {
-	    this.name = "HolochainTestError";
-	    this.message = (message || "");
-	}
-	HolochainTestError.prototype = Error.prototype;
+    function HolochainTestError(message) {
+      this.name = "HolochainTestError";
+      this.message = (message || "");
+    }
+    HolochainTestError.prototype = Error.prototype;
 
-	try {
-	    COMB.debug();
-	    const parent	= await COMB.listen({
-		"test": async function ( ...args ) {
-		    return "Hello World: " + JSON.stringify(args);
-		},
-		"test_synchronous": function () {
-		    return "Hello World";
-		},
-		"test_error": function ( ...args ) {
-		    return new HolochainTestError("Method did not succeed\n" + JSON.stringify(args));
-		},
-		"test_synchronous_error": function () {
-		    return new HolochainTestError("Method did not succeed");
-		}
-		});
-	} catch ( err ) {
-	    console.error( String(err) );
-	}
-    })();
+    try {
+      COMB.debug();
+      const parent = await COMB.listen({
+        "test": async function (...args) {
+          return "Hello World: " + JSON.stringify(args);
+        },
+        "test_synchronous": function () {
+          return "Hello World";
+        },
+        "test_signal": function (signal) {
+          return parent.sendSignal(signal)
+        },
+        "test_error": function (...args) {
+          return new HolochainTestError("Method did not succeed\n" + JSON.stringify(args));
+        },
+        "test_synchronous_error": function () {
+          return new HolochainTestError("Method did not succeed");
+        }
+      });
+    } catch (err) {
+      console.error(String(err));
+    }
+  })();
 </script>
diff --git a/src/index.ts b/src/index.ts
index 19d0896..6041616 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -73,8 +73,8 @@ const COMB = {
    * @example
    * const child = await COMB.connect( "http://localhost:8002" );
    */
-  async connect(url, timeout) {
-    const child = new ChildAPI(url, timeout);
+  async connect(url, timeout, signalCb) {
+    const child = new ChildAPI(url, timeout, signalCb);
     await child.connect();
     return child;
   },
@@ -115,21 +115,23 @@ class ChildAPI {
   handshake: any;
   class_name: string;
   loaded: boolean;
+  signalCb: any;
 
   /**
    * Initialize a child frame using the given URL.
    * 
    * @class ChildAPI
    * 
-   * @param {string} url		- URL that is used as 'src' for the iframe
+   * @param {string} url - URL that is used as 'src' for the iframe
    * 
-   * @prop {string} url 		- iFrame URL
-   * @prop {number} msg_count		- Incrementing message ID
-   * @prop {object} responses		- Dictionary of request Promises waiting for their responses
-   * @prop {object} msg_bus		- Postmate instance
-   * @prop {promise} handshake	- Promise that is waiting for connection confirmation
-   * @prop {string} class_name	- iFrame's unique class name
-   * @prop {boolean} loaded		- Indicates if iFrame successfully loaded
+   * @prop {string} url         - iFrame URL
+   * @prop {number} msg_count   - Incrementing message ID
+   * @prop {object} responses   - Dictionary of request Promises waiting for their responses
+   * @prop {object} msg_bus     - Postmate instance
+   * @prop {promise} handshake  - Promise that is waiting for connection confirmation
+   * @prop {string} class_name  - iFrame's unique class name
+   * @prop {boolean} loaded     - Indicates if iFrame successfully loaded
+   * @prop {any} signalCb       - A callback that's run when we receive a signal
    * 
    * @example
    * const child = new ChildAPI( url );
@@ -138,12 +140,14 @@ class ChildAPI {
    * await child.set("mode", mode );
    * let response = await child.run("signIn");
    */
-  constructor(url, timeout = 5_000) {
+  constructor(url, timeout = 5_000, signalCb) {
     this.url = url;
     this.msg_count = 0;
     this.responses = {};
     this.loaded = false;
 
+    this.signalCb = signalCb;
+
     this.class_name = "comb-frame-" + ChildAPI.frame_count++;
     this.handshake = async_with_timeout(async () => {
       // log.info("Init Postmate handshake");
@@ -186,8 +190,7 @@ class ChildAPI {
         if (this.loaded) {
           // log.error("iFrame loaded but could not communicate with COMB");
           throw new TimeoutError("Failed to complete COMB handshake", err.timeout);
-        }
-        else {
+        } else {
           // log.error("iFrame did not trigger load event");
           throw new TimeoutError("Failed to load iFrame", err.timeout);
         }
@@ -212,6 +215,10 @@ class ChildAPI {
       delete this.responses[k];
     });
 
+    if (this.signalCb) {
+      child.on('signal', this.signalCb)
+    }
+
     this.msg_bus = child;
 
     return this;
@@ -223,9 +230,9 @@ class ChildAPI {
    * @async
    * @private
    * 
-   * @param {string} method		- Internally consistent Postmate method
-   * @param {string} name		- Function name or property name
-   * @param {*} data			- Variable input that is handled by child API
+   * @param {string} method   - Internally consistent Postmate method
+   * @param {string} name     - Function name or property name
+   * @param {*} data          - Variable input that is handled by child API
    * 
    * @return {*} Response from child
    */
@@ -256,8 +263,8 @@ class ChildAPI {
    * 
    * @async
    * 
-   * @param {string} key		- Property name
-   * @param {*} value			- Property value
+   * @param {string} key  - Property name
+   * @param {*} value     - Property value
    * 
    * @return {boolean} Success status
    * 
@@ -303,13 +310,13 @@ class ParentAPI {
    * 
    * @class ParentAPI
    * 
-   * @param {object} methods		- Functions that are available for the parent to call.
-   * @param {object} properties	- Properties to memorize in the instance for later use, optional
+   * @param {object} methods    - Functions that are available for the parent to call.
+   * @param {object} properties - Properties to memorize in the instance for later use, optional
    * 
-   * @prop {promise} listener		- Promise that is waiting for parent to connect
-   * @prop {object} msg_bus		- Postmate instance
-   * @prop {object} methods		- Method storage
-   * @prop {object} properties	- Set properties storage
+   * @prop {promise} listener   - Promise that is waiting for parent to connect
+   * @prop {object} msg_bus     - Postmate instance
+   * @prop {object} methods     - Method storage
+   * @prop {object} properties  - Set properties storage
    * 
    * @example
    * const parent = new ParentAPI({
@@ -320,6 +327,7 @@ class ParentAPI {
    * await parent.connect();
    */
   constructor(methods, properties = {}) {
+
     this.methods = methods;
     this.properties = properties;
 
@@ -367,12 +375,31 @@ class ParentAPI {
    * });
    * await parent.connect();
    */
-  async connect() {
+  async connect () {
     this.msg_bus = await this.listener;
 
     return this;
   }
 
+    /**
+   * Send holochain conductor signal to parent.
+   * 
+   * @async
+   * 
+   * @param {object} signal		- The signal
+   * 
+   * @example
+   * const parent = new ParentAPI({
+   *     "hello": async function () {
+   *         return "Hello world";
+   *     }
+   * });
+   * await parent.sendSignal(signal);
+   */
+  async sendSignal (signal) {
+    this.msg_bus.emit('signal', signal)
+  }
+
 }
 
 export {
diff --git a/tests/integration/test_comb.js b/tests/integration/test_comb.js
index 5611369..18f4428 100644
--- a/tests/integration/test_comb.js
+++ b/tests/integration/test_comb.js
@@ -159,6 +159,28 @@ describe("Testing COMB", function () {
     }
   });
 
+  it("should call the provided signalCb when sendSignal is called on the parent", async function () {
+    try {
+      // have to setup our spy function in the puppeteer evaluation context
+      await page.evaluate(() => {        
+        window.signalCb = function(signal) {
+          window.signalCbCalledWith = signal
+        }
+      });
+
+      const expectedSignal = "Hello COMB";
+
+      const signalCbCalledWith = await page.evaluate(async function (chap_url, expectedSignal) {
+        window.child = await COMB.connect(chap_url, 5000, window.signalCb);
+        await child.run("test_signal", expectedSignal);
+        return window.signalCbCalledWith
+      }, chap_url, expectedSignal);
+
+      expect(signalCbCalledWith).to.equal(expectedSignal);
+    } finally {
+    }
+  });
+
   it("should timeout because of wrong frame URL", async function () {
     try {
       const result = await page.evaluate(async function () {