Voice Over Internet Protocol (VOIP) is a much less costly technology when compared to the traditional telephonic services. VOIP provides much more flexibility than the traditional ones in terms of telecommunication and offers various features, such as multiple extensions, caller ID services, logging, a recording of each call made, and so on. Various companies have launched their Private branch exchange (PBX) on enabled IP phones these days.

Traditional and present telephonic system is still vulnerable to interception through physical access, such as if an attacker alters the connection of a phone line and attaches his transmitter. He will be able to make and receive calls to his device and can enjoy Internet and fax services.

However, in the case of VOIP services, we can compromise security without going on to the wires. Nevertheless...