diff --git a/types/serialport/index.d.ts b/types/serialport/index.d.ts
index 14ded3b6e3..c1a81376fa 100644
--- a/types/serialport/index.d.ts
+++ b/types/serialport/index.d.ts
@@ -103,7 +103,7 @@ declare namespace SerialPort {
 			constructor(options: {delimiter: string | Buffer | number[], encoding?: 'ascii'|'utf8'|'utf16le'|'ucs2'|'base64'|'binary'|'hex'});
 		}
 		class Ready extends Stream.Transform {
-			constructor(options: {data: string | Buffer | number[]});
+			constructor(options: {delimiter: string | Buffer | number[]});
 		}
 		class Regex extends Stream.Transform {
 			constructor(options: {regex: RegExp});
diff --git a/types/serialport/serialport-tests.ts b/types/serialport/serialport-tests.ts
index 16cf2b6a70..d6541a63c2 100644
--- a/types/serialport/serialport-tests.ts
+++ b/types/serialport/serialport-tests.ts
@@ -107,7 +107,7 @@ function test_parsers() {
     const CCTalkParser = new SerialPort.parsers.CCTalk();
     const DelimiterParser = new SerialPort.parsers.Delimiter({ delimiter: Buffer.from('EOL') });
     const ReadlineParser = new SerialPort.parsers.Readline({ delimiter: '\r\n' });
-    const ReadyParser = new SerialPort.parsers.Ready({ data: 'READY' });
+    const ReadyParser = new SerialPort.parsers.Ready({ delimiter: 'READY' });
     const RegexParser = new SerialPort.parsers.Regex({regex: /.*/});
 
     port.pipe(ByteLengthParser);