Harris & Jeffries Inc, the Dedham, Massachusetts-based supplier of asynchronous transfer mode, frame relay and cell relay software to the likes of 3Com Corp, Ascend Communications Inc, Bay Networks Inc, Cabletron Systems Corp, Intel Corp and others, says it has achieved the highest cell per second ratings ever announced by any ATM vendor. The company says it achieved a cell rate of over 4,800 CPS on a Windows NT 4.0-based 180MHz Pentium system running its Soft-ATM toolkit.