When an IP system is in place, information is sent from a resident's ID card, through the reader, and on to a server. That information could be something as basic as a PIN number or as sophisticated as live video. IP control systems must first organise and package data according to a set of rules called protocols before sending it over the internet. IP control systems get their moniker because they rely on, among other things, the Internet Protocol. Some service providers refer to these systems as TCP/IP access control systems because TCP is another essential set of restrictions. Voice over Internet Protocol refers to an established protocol for the transmission and reception of sound over the Internet (VoIP). VoIP is commonly used by internet-based door entry systems to provide phone entry.