The departments and sites share the same group of 100 department quick keys for each system. You can assign a different department quick key to each site. You should be holding on a system to toggle departments or sites on and off. The system must be scanning. Press the decimal point button twice followed by the department or site quick key number followed by E. That will toggle that department or site on and off. For each system, it is better to group the department quick keys in the lower numbers and the site quick keys in higher numbers for simplicity. For example, if you have 10 or fewer departments, you can use department quick keys 0 thru 9 for the departments and department quick keys 10 and above for sites. If you have only 5 departments, you can use department quick keys 0 thru 4 for departments and department quick keys 5 and above for sites. How you arrange it is up to you.