diff --git a/common/JackNetDriver.cpp b/common/JackNetDriver.cpp
index 8c8d1bf4..38fe48e7 100644
--- a/common/JackNetDriver.cpp
+++ b/common/JackNetDriver.cpp
@@ -575,7 +575,7 @@ namespace Jack
         }
         for (int audio_port_index = 0; audio_port_index < fPlaybackChannels; audio_port_index++) {
         #ifdef OPTIMIZED_PROTOCOL
-            // Port is connected on other side..
+            // Port is connected on other side...
             if ((long)fNetAudioPlaybackBuffer->GetBuffer(audio_port_index) == -1) {
                 fNetAudioPlaybackBuffer->SetBuffer(audio_port_index, GetOutputBuffer(audio_port_index, true));
             } else {
diff --git a/common/JackNetManager.cpp b/common/JackNetManager.cpp
index c3cb85eb..7601acdd 100644
--- a/common/JackNetManager.cpp
+++ b/common/JackNetManager.cpp
@@ -432,6 +432,7 @@ namespace Jack
 
         #ifdef OPTIMIZED_PROTOCOL
             if ((long)fNetAudioCaptureBuffer->GetBuffer(audio_port_index) == -1) {
+                // Port is connected on other side...
                 fNetAudioCaptureBuffer->SetBuffer(audio_port_index,
                                                 static_cast<sample_t*>(jack_port_get_buffer_nulled(fAudioCapturePorts[audio_port_index],
                                                 fParams.fPeriodSize)));
diff --git a/common/JackNetTool.h b/common/JackNetTool.h
index cfceee13..238b075a 100644
--- a/common/JackNetTool.h
+++ b/common/JackNetTool.h
@@ -614,6 +614,7 @@ namespace Jack
             }
 
             for (uint port_index = 0; port_index < port_num; port_index++) {
+                // Use -1 when port is actually connected on other side
                 fPortBuffer[*active_port_address] = (sample_t*)-1;
                 active_port_address++;
             }
diff --git a/tests/iodelay.cpp b/tests/iodelay.cpp
index 4ef90fb0..924c818b 100644
--- a/tests/iodelay.cpp
+++ b/tests/iodelay.cpp
@@ -235,14 +235,18 @@ int main (int ac, char *av [])
         if (mtdm.resolve () < 0) printf ("Signal below threshold...\n");
         else
         {
+            jack_nframes_t systemic_latency;
             if (mtdm.err () > 0.3)
             {
                 mtdm.invert ();
                 mtdm.resolve ();
             }
-            printf ("%10.3lf frames %10.3lf ms", mtdm.del (), mtdm.del () * t);
-            if (mtdm.err () > 0.2) printf (" ??");
-                if (mtdm.inv ()) printf (" Inv");
+            systemic_latency = (jack_nframes_t) floor (mtdm->_del - (capture_latency.max + playback_latency.max));
+
+            printf ("%10.3lf frames %10.3lf ms total roundtrip latency\n\textra loopback latency: %u frames\n\tuse %u for the backend arguments -I and -O", mtdm->_del, mtdm->_del * t,
+                    systemic_latency, systemic_latency/2);
+            if (mtdm->_err > 0.2) printf (" ??");
+                if (mtdm->_inv) printf (" Inv");
             printf ("\n");
         }
     }