diff --git a/modem-tester.js b/modem-tester.js
index d8115a0..56b7bf3 100644
--- a/modem-tester.js
+++ b/modem-tester.js
@@ -47,8 +47,7 @@ port = new SerialPort(config.modem.device, { baudRate: 115200 }, async (err) =>
         process.exit(1);
     }
 
-    await writeToPortDelayed('AT\r');
-
+    await modemCommands.writeToPortAndWaitForOkOrError('AT\r');
     await modemCommands.writeToPortAndWaitForOkOrError('AT&FE0\r');
     await modemCommands.writeToPortAndWaitForOkOrError('AT+CMGF=0\r');
     await modemCommands.writeToPortAndWaitForOkOrError('AT+CNMI=1,2,0,1,0\r');