OSX Mavericks (10.9) introduced a feature called App Nap. This allows the operating system to reduce resources to programs that aren't prominently operating in the foreground, therefore speeding up your computer. This doesn't always play nice with applications that require constant networking or database features.
How to Fix it
First make sure you are up to date with your version of Roll Call. 12.0.22 was the first version to be released that was officially supported by OSX Mavericks and Windows 8.1.
Now, to turn off "App Nap" for Roll Call:
1. ) Go to "Get Info" (Right Click on the RollCall application in finder - First screenshot)
2. ) Check the box that says "Prevent App Nap." (Second Screenshot)
3. ) Restart Roll Call
Note: If you have Client/Server installed, the steps are the same.
Please make sure you restart your Roll Call Server/Standalone App after changing this preference.