McDonnell Douglas Systems company Tymnet Inc has introduced two mid-range packet switches to expand its product line, and has slashed earlier models by 50%. The Mini Engine XL and the Dual Mini Engine XL slot between and are compatible with another recent high-end addition called Turbo and the low-end Pico engines. The XL engines use proprietary, modular processors Tymnet traditionally builds a bit-slice CPU – which provide performance of 400 packets per second for the Mini XL and double that for the Dual Mini XL which combines two Minis in a single box. Tymnet claims that Open Systems architecture will eventually be extended down from the top-end Turbo through the product line over the next five years. The XL hardware is priced according to the system configuration and ranges from $35,000 to $45,000 for the Mini and $65,000 to $80,000 for the larger model.