NORTHERN Telecom has secured a 10-year supply contract worth nearly US$100 million over the next two years. The Canadian manufacturer of telecommunications equipment will supply the infrastructure for phase two of the Mercury One-2-One Personal Communications Network in Britain. Installation is to start before the end of this year. The agreement will give Mercury Personal Communications a turnkey GSM-based (Groupe Speciale Mobile) digital cellular system. The contract will also provide Mercury with Northern Telecom's mobile switching and radio base station technology as well as its Smart antenna technology. Mercury will have access to a wide range of advanced features in Northern Telecom's Mobile Services Switching Centre. Additional service features will allow Mercury to implement closed user groups and private number plans. It will also facilitate the configuration of special features for both private and business users. David Twyver, president of Northern Telecom Wireless Systems, said: ''We find growing customer acceptance of our digital cellular networks portfolio, low-and high-tier PCS networks and wireless access networks. We are the only wireless manufacturer todaywith contracts in all of these market segments.'' Northern Telecom's revenue reached US$8.15 billion in 1993. It has wholly owned and joint-venture manufacturing operations in Malaysia, Thailand, Australia and China. Northern Telecom provides DMS digital switching systems, Meridien private branch exchanges, multimedia communications solutions and a range of optical fibre transmission and cable products.