A monolithic module acting as the interface between a modem and leased ("LL") or switched ("SL") telephone lines, mainly characterized in that: 1. It can be formed on a silicon chip (due to the absence of electromechanical relays or similar switching means), and 2. Its architecture is such that it makes...http://www.google.de/patents/US4607139?utm_source=gb-gplus-sharePatent US4607139 - Interface module for telephone lines
