Users can observe and communicate with guests at a door or gate remotely with the help of IP-based video intercom systems, a sort of access control system. A camera at the entry point is linked to the user's system through an IP network to enable the system to function. The guest can then be seen on a monitor or mobile device, and two-way audio can be used to speak with them. Using the same device, the user might also be able to remotely unlock the entrance or gate depending on the system. When compared to more conventional intercoms, including telephone entry systems, IP-based video intercom systems offer a greater range of functions.