For enterprises that want to evolve their communication infrastructures into a IP environment, they often find it hard to ditch their legacy equipment. For hotels and enterprises with a large quantity of analog phones, it is not cost-saving to replace every one of them with IP phones all at once. And sometimes fax machines, postage machines, alarm systems do not function reliably over IP networks. In this case, you could integrate legacy equipment to the local IP system with TransVoice. As a result, analog endpoints could utilize IP-PBX functionalities cost-effectively.
There may also be instances where PABX need to be integrated with a remote IP-PBX. In this scenario, the branch office and the headquarter have their own telephone system, one with an IP-PBX, the other with a PABX. It is natural that the two offices want to communicate cheaply and conveniently. With the integration, the office-to office calling becomes free with no long-distance charges. And the analog endpoints could also benefit from the VoIP access of the IP-PBX.