diff --git a/lib/modem/index.js b/lib/modem/index.js
index fc81d72..88cf3fb 100644
--- a/lib/modem/index.js
+++ b/lib/modem/index.js
@@ -40,6 +40,7 @@ class Modem extends EventEmitter {
         this.port = new SerialPort(this.portName);
 
         this.port.on('error', function(err) {
+            debugLog('MODEM: error opening ' + this.portName);
             if (cb) cb(err);
         });