Index: trunk/FACT++/src/biasctrl.cc
===================================================================
--- trunk/FACT++/src/biasctrl.cc	(revision 13108)
+++ trunk/FACT++/src/biasctrl.cc	(revision 13109)
@@ -2004,6 +2004,9 @@
         fBias.SetVerbose(!conf.Get<bool>("quiet"));
 
-        fBias.SetEndpoint(conf.Get<string>("dev"));
-        T::Message("Setting device to "+fBias.URL());
+        if (conf.Has("dev"))
+        {
+            fBias.SetEndpoint(conf.Get<string>("dev"));
+            T::Message("Setting device to "+fBias.URL());
+        }
 
         const uint16_t step = conf.Get<uint16_t>("ramp-step");
@@ -2087,5 +2090,6 @@
         // --------------------------------------------------------------------------
 
-        fBias.Connect();
+        if (conf.Has("dev"))
+            fBias.Connect();
 
         return -1;
@@ -2108,5 +2112,5 @@
     control.add_options()
         ("no-dim,d",        po_bool(),  "Disable dim services")
-        ("dev",             var<string>("FTE00FOH"),  "Device address of USB port to bias-power supply")
+        ("dev",             var<string>(),       "Device address of USB port to bias-power supply")
         ("quiet,q",         po_bool(),           "Disable printing contents of all received messages (except dynamic data) in clear text.")
         ("ramp-delay",      var<uint16_t>(15),   "Delay between the answer of one ramping step and sending the next ramp command to all channels in milliseconds.")