As mentioned, VOIP telephone systems provide all the same capabilities of a traditional PSTN phone systems, yet they do not cost as much to implement and run. Voice mail, caller ID, call forwarding, auto attendant, and follow me call forwarding are all present. Voice mail and email may now become synonymous when voice recorded emails are transcribed to email for easy reading. Local phone numbers and toll free numbers are provided with most VOIP PBX system.

Open standards allow for customisation and flexibility of the VOIP PBX system. With Open standards, proprietary technology can be integrated into the existing system and offer added protection against security breaches. Businesses can also take advantage of add-ons such as technology to operate fax machines, card payment systems, and other security features.

VoIP is popular with organisations seeing rapid expansion as the system is highly portable and easy to install and use. A switch is connected to the router and Local Area Network (LAN). The VOIP phone is in then connected to the switch and calls can be completed. This installation process is easy and adding a phone line is simple. With this set up, an employee can use their direct line in or outside the office.

For small companies of 5 employees or less, 90 kbits per second transmission is necessary for each phone line. A more extensive network may be needed for companies with more than 100 employees. A general PBX system works by converting circuit switched outputs that originate from the PBX system into IP packets. These data packets are then are sent to the router and through T1 or T3 lines. To use this type of system, most companies must secure business broadband internet to support multiple calls with no interruptions.

Companies seeking to invest in a VOIP PBX system will require minimal investment. Small companies may spend under $1,000 for the system. Larger organisations will have to spend more. The unique aspect of VOIP PBX is that each conversation can be easily recorded and transcribed to text because every conversation is digitized. For future use, conversations can be recorded and either stored on a hard drive or burnt onto a CD-R or DVD.

Mitel offers businesses several Mitel VOIP PBX systems that can accommodate businesses as small as 30, as well as, businesses with 60,000 users. These particular phone systems have multiple features. Most Mitel phones have over 500 features available to a user including ACD, wireless gateway, auto attendant, and unified messaging. Wireless handsets are also available. The system is scalable and easy to maintain and install.

The Avaya 1616 is one smart phone. It doubles as a conference phone and has a multiple caller facility, making the Avaya 1616 ideal for the home.