Plessey Communications Systems, the sales arm for Plessey’s ISDX digital PABX has won a UKP3m order with the Department of Health and Social Security to set up and install a nationwide digital network based on the ISDX: the company is to supply 57 exchanges in various sizes, varying from 40 to 400 exchange lines; maintenance of the network over 10 years is worth another UKP1m.