A system for determining the transmit power of a communication device operating on a twisted pair subscriber line includes a communication server coupled to a first subscriber line and a second subscriber line. The communication server comprises a communication device that communicates a signal using...http://www.google.com.tw/patents/US6636603?utm_source=gb-gplus-share專利 US6636603 - System and method for determining the transmit power of a communication device operating on digital subscriber lines
