In order to connect to a Frame Relay network, both DTE and DCE equipment needs to be located at the customer premises. This DTE equipment is usually a router, whose serial interface connects to a DCE device. In the past, customers required a completely separate DTE device known as a Frame Relay Access Device (FRAD) to connect to a Frame Relay network. However, almost all routers sold today (with an appropriate serial interface) are capable of handling Frame Relay encapsulation and communication. The DCE device is usually a CSU/DSU that provides clocking functions and the connection to the provider’s physical circuit. Ultimately, the physical link from the customer premises connects to the Frame Relay switching equipment of the service provider. This switching equipment is not the responsibility of the customer. The figure below illustrates the interconnections of equipment on a Frame Relay network.