Method of communication through leased line in virtual...
Network linkage type private branch exchange system and...
Non-notified centralized operator in private telecommunication n
PBX call management
Private automatic branch exchange (PABX) system with transparent
Private branch exchange networks
Rapid response to user input at a telecommunications terminal
Remote PBX system and advanced communication terminals
Rules-based call routing
Signaling method and network element for a virtual private...
Signaling system and method for enabling PBX-PBX feature transpa
System and method for providing communication on a wide area net
Telecommunication system and method for implementing an ISDN...
Telephone tie trunk driver circuit
Virtual private line connection system and method