Nortel Modular ICS Key Service Unit. with 4 incoming lines and 32 telephone station ports. Expandable phone system. A Norstar Modular ICS system MICS provides increased processing power, networking capability and advanced features that can be customized to fit both present and future communications needs. The Modular ICS has the ability to integrate high value applications to the phone system as the business need arises: advanced Voice Mail, Call Center Applications, integrated Mobility, Internet Access, ISDN and Desktop CTI.