diff --git a/Setup-Computer-Debian-13.md b/Setup-Computer-Debian-13.md
index 38f029d..8b7c7ef 100644
--- a/Setup-Computer-Debian-13.md
+++ b/Setup-Computer-Debian-13.md
@@ -156,9 +156,10 @@ cd ~/work/stxm/build/PixelatorController
 
 # run GUI in 2nd Terminal
 cd ~/work/stxm/build/PixelatorGUI
-./scripts/PixelatorGUI-nH # -nH for no Hardware uses Ports 56561 and 56562
+./scripts/PixelatorGUI-nH     # -nH for no Hardware
 
 ```
+Note that the no-hardware version of PixelatorGUI uses ports 56561 and 56562 by default. To configure the ports (need to match those configured for PixelatorController), edit the `[Resource]` section at the beggining of the `*.ini` files in `build/PixelatorGUI/etc/`.
 
 - compile Orocos modules
 ```