F Westford, Massachusetts-based Cascade Communications Corp has added Frame Relay Switched Virtual Circuits to its Multiservice WAN Switch products, claiming to be the first vendor to do so. The technology was developed jointly with Advanced Compression Technology Inc, which will use it within its SDM-FP network access multiplexers. The companies say that their implementation corresponds to the Frame Relay Forum and CCITT recommendations, and that it will interoperate with Asynchronous Transfer Mode Switched Virtual Circuits when they become available. Cascade also says that when used with its ISDN PRI Access Module, users can establish end-to-end switched services. Frame Relay Switched Virtual Circuits will be optional on the company’s products from April, costing $5,000 on the STDX 3000 and 6000 systems, and $10,000 on the B-STDX 9000.