diff --git a/lib/modem/index.js b/lib/modem/index.js
index 26545a0..fc81d72 100644
--- a/lib/modem/index.js
+++ b/lib/modem/index.js
@@ -36,6 +36,7 @@ class Modem extends EventEmitter {
     open(cb) {
         const self = this;
 
+        debugLog('MODEM: opening ' + this.portName);
         this.port = new SerialPort(this.portName);
 
         this.port.on('error', function(err) {