The Communications Center is the central location for both system-wide and project-wide communications.
Action items (AIs) are your to-do list. Here you can update your tasks, and create tasks for others. Action items are specific to the project you are currently viewing so to ensure you see all your AIs, go into each project in your portfolio and check your Communications Center.
The Low setting will inform only of high importance field changes; the High setting will inform of all field changes (useful for Project Managers and very nosey people), and the Medium setting will inform only of medium to high importance field changes.
In the Communications Center you will be notified of the importance of the field that was changed, and how specifically the value changed. The Timestamp indicates the timing of the change. Clicking the Get history button produces a screen that displays each change in more detail.
Messages are in-system email-style messages to other TCP users within your project. You can type messages, add attachments, CC others, forward messages, and use all the other functions you expect from a messaging system. Using TCP messaging maintains all communication records within one system, and by doing so, will lessen the whoopsies that result in using multiple channels.