diff --git a/lib/serialport-parsers.js b/lib/serialport-parsers.js
index 2853fe4..845f2e7 100644
--- a/lib/serialport-parsers.js
+++ b/lib/serialport-parsers.js
@@ -119,7 +119,7 @@ parserReadline.on('data', (data) => {
         logger.warn('Unknown PDU message type name. PLEASE REPORT IT TO DEVELOPER AT TEKTRANS', { typeName: pduParsed.constructor.name, type: pduParsed.getType(), data: data.toString().trim() });
     }
 
-    if (pduParsed && pduParsed.constructor.name === 'Deliver' && pduParsed.getType && pduParsed.getType().getSrr()) {
+    if (pduParsed && pduParsed.constructor.name === 'Deliver' && pduParsed.getData().getSize()) {
         logger.verbose('Got a PDU SMS-DELIVER', { type: pduParsed.getType() });
         onPduDeliver(data, pduParsed);
     } else if (isResultCodeIs(data, 'CSQ')) {