The present invention is directed to a message interfacing agent 224 enables a circuit-switched communication device 106, such as a telephone, to receive and respond to electronic messages and the feature server 228 enables external endpoints to access switch/server functionality using packet-switched...http://www.google.fr/patents/US7412044?utm_source=gb-gplus-shareBrevet US7412044 - Instant messaging to and from PBX stations
