A method and system provide seamless, wireless telecommunication service to customers that move between disparate networks that use different protocols. A Universal Location Service Register (ULSR) communicates and provides mobility management and authentication functions across networks that use different...http://www.google.com.tw/patents/US6697620?utm_source=gb-gplus-share專利 US6697620 - Method and system for providing telecommunication services across networks that use different protocols
