diff --git a/lib/modem.js b/lib/modem.js
index ee430b3..22d51c8 100644
--- a/lib/modem.js
+++ b/lib/modem.js
@@ -324,6 +324,10 @@ function executeUSSD(code, includeCUSD2) {
         const parserMain = new ParserReadline({ delimiter: '\r\n' });
         // const parserMain = new ParserRegex({ regex: REGEX_WAIT_FOR_OK_OR_ERROR });
         parserMain.on('data', (data) => {
+            if (!data || !data.toString().trim()) return;
+
+            if (data.toString().trim() === 'OK') return;
+
             port.unpipe(parserMain);
             mutex.releaseLockWaitForSubCommand();
             resolve(data);