Basic principles
RCS enables multimedia bidirectional communication between devices that have the RCS service active. No special application needs to be installed – RCS is a native part of Android OS. The customer thus sees the conversation directly in the messaging app along with the SMS. RCS supports features such as group conversations, typing indication, message read and voice calls, as well as file transfer up to 100 MB in size. RCS also allows users to see when their contacts are online, like instant messaging apps.