diff --git a/README.md b/README.md
index 269d30b6..4a16c088 100644
--- a/README.md
+++ b/README.md
@@ -58,7 +58,8 @@ The following Visual Studio Code settings are available for the Arduino extensio
     "arduino.commandPath": "run-arduino.bat",
     "arduino.additionalUrls": "",
     "arduino.logLevel": "info",
-    "arduino.enableUSBDetection": true
+    "arduino.enableUSBDetection": true,
+    "arduino.disableTestingOpen": false
 }
 ```
 - `arduino.path` - Path to Arduino, you can use a custom version of Arduino by modifying this setting to include the full path. Example: `C:\\Program Files\\Arduino` for Windows, `/Applications` for Mac, `/home/$user/Downloads/arduino-1.8.1` for Linux. (Requires a restart after change). The default value is automatically detected from your Arduino IDE installation path.
@@ -66,6 +67,7 @@ The following Visual Studio Code settings are available for the Arduino extensio
 - `arduino.additionalUrls` - Additional URLs for 3rd party packages. You can have multiple URLs in one string with comma(,) as separator, or have a string array. The default value is empty.
 - `arduino.logLevel` - CLI output log level. Could be info or verbose. The default value is `"info"`.
 - `arduino.enableUSBDetection` - Enable/disable USB detection from the VSCode Arduino extension. The default value is `true`.
+- `arduino.disableTestingOpen` - Disable/enable auto sending a test message to serial port for checking open status. The default value is `false` (a test message will be sent).
 
 The following settings are per sketch settings of the Arduino extension. You can find them in
 `.vscode/arduino.json` under the workspace.
diff --git a/package.json b/package.json
index 8037e431..1132c2df 100644
--- a/package.json
+++ b/package.json
@@ -436,6 +436,10 @@
         "arduino.enableUSBDetection": {
           "type": "boolean",
           "default": true
+        },
+        "arduino.disableTestingOpen": {
+          "type": "boolean",
+          "default": false
         }
       }
     },
diff --git a/src/arduino/vscodeSettings.ts b/src/arduino/vscodeSettings.ts
index 408760c9..bc9f43ce 100644
--- a/src/arduino/vscodeSettings.ts
+++ b/src/arduino/vscodeSettings.ts
@@ -10,6 +10,7 @@ const configKeys = {
     LOG_LEVEL: "arduino.logLevel",
     AUTO_UPDATE_INDEX_FILES: "arduino.autoUpdateIndexFiles",
     ENABLE_USB_DETECTOIN: "arduino.enableUSBDetection",
+    DISABLE_TESTING_OPEN: "arduino.disableTestingOpen",
 };
 
 export interface IVscodeSettings {
@@ -18,6 +19,7 @@ export interface IVscodeSettings {
     additionalUrls: string | string[];
     logLevel: string;
     enableUSBDetection: boolean;
+    disableTestingOpen: boolean;
     updateAdditionalUrls(urls: string | string[]): void;
 }
 
@@ -53,6 +55,10 @@ export class VscodeSettings implements IVscodeSettings {
         return this.getConfigValue<boolean>(configKeys.ENABLE_USB_DETECTOIN);
     }
 
+    public get disableTestingOpen(): boolean {
+        return this.getConfigValue<boolean>(configKeys.DISABLE_TESTING_OPEN);
+    }
+
     public async updateAdditionalUrls(value) {
         await this.setConfigValue(configKeys.ADDITIONAL_URLS, value, true);
     }
diff --git a/src/serialmonitor/serialportctrl.ts b/src/serialmonitor/serialportctrl.ts
index 5a252093..cc282773 100644
--- a/src/serialmonitor/serialportctrl.ts
+++ b/src/serialmonitor/serialportctrl.ts
@@ -3,6 +3,7 @@
 
 import * as os from "os";
 import { OutputChannel, QuickPickItem, StatusBarAlignment, StatusBarItem, window } from "vscode";
+import { VscodeSettings } from "../arduino/vscodeSettings";
 
 interface ISerialPortDetail {
   comName: string;
@@ -78,6 +79,11 @@ export class SerialPortCtrl {
         this._currentSerialPort = new SerialPortCtrl.serialport(this._currentPort, { baudRate: this._currentBaudRate });
         this._outputChannel.show();
         this._currentSerialPort.on("open", () => {
+          if (VscodeSettings.getInstance().disableTestingOpen) {
+            this._outputChannel.appendLine("[Warning] Auto checking serial port open is disabled");
+            return resolve();
+          }
+
           this._currentSerialPort.write("TestingOpen", "Both NL & CR", (err) => {
             // TODO: Fix this on the serial port lib: https://github.com/EmergingTechnologyAdvisors/node-serialport/issues/795
             if (err && !(err.message.indexOf("Writing to COM port (GetOverlappedResult): Unknown error code 121") >= 0)) {