You probably have either :
1. Hit some quickkeys. While in scan mode enter keys 1-0 while watching the bottom of the display. Pressing the button toggles them on and off. The systems are the top row.
2. Locked something out. More likely if you are missing the whole system, it is the keys above. If lockouts, you will need to scroll through the systems, departments and channels and review the lockout status.
Mark
WS1095/536/996P2/HP1e/HP2e/996XT/325P2/396XT/PRO668/PSR800/PRO652