The E4204A HSSI Line Interface is a physical line interface implemented in a single-slot VXI module for the modular Agilent Broadband Series Test System. It transmits and receives data at line rates ranging from 1 Mb/s up to 52Mb/s. The E4204A HSSI Line Interface module performs physical layer testing. Used in conjunction with an E4209 Cell Protocol Processor module and E4213 DXI Test Software, the E4204A will monitor and simulate the SMDS Data Exchange Interface (DXI) protocol. In addition, when used with an E4209 Cell Protocol Processor module and E6279A Frame Relay over HSSI Test Software, the E4204A facilitates testing Frame Relay permanent virtual circuit (PVC) operation over a HSSI interface.