It is possible to connect ​​​a CTC-1402 pair to an input of another CTC Pair without a control system and utilize only auto input selection.  This includes passing of USB.  

​​Follow the connection diagram below.  The stars represent the default input (HDMI 1).  With no other active video source and 'auto mode' enabled the CTCs default to this HDMI input—normally used for a room PC.  For simplicity 'CTC Pair A' will be called 'CTC-A' and 'CTC Pair B' will be 'CTC-B'.  

​1. The Room PC will be the default video source if CTC-A and CTC-B have no other active video sources.  

2.  Any single active video source connected to either CTC-A or CTC-B will be prioritized.  

CTC-A will always have priority. Scen​​​​​​arios:

CTC-A has an active video source connected.  A new video source is then introduced on CTC-B.  This new video source will not take priority until the video source on CTC-A is removed.​  

​​CTC-B has an active video source connected.  A new video source is then introduced on CTC-A.  The new source on CTC-A will take priority.  

​If a control syst​​em is used and auto mode is disabled, then it would be possible to custom prioritize inputs.  The CTC does provide unsolicited messages when a video source connects and disconnects.  With this unsolicited information, prioritization can be determined within code and switch commands be sent accordingly.