Endpoint systems have the advantage that they can monitor and control access to physical devices (such as mobile devices with data storage capabilities) and in some cases can access information before it is encrypted. Some endpoint-based systems provide application controls to block attempted transmissions of confidential information and provide immediate user feedback. They must be installed on every workstation in the network, cannot be used on mobile devices (e.g., cell phones and PDAs) or where they cannot be practically installed (for example on a workstation in an Internet café).