While small and medium businesses have been cautious about adopting Voice over IP (VoIP) phone service in a big way, IP-based extensions are rapidly replacing digital and analog phones. This is not surprising, given their advantages, the most significant of which is the fact that most are standards-based, meaning a buyer can mix and match phone systems and phones. Given that phones are often 75% of the total purchase price of a phone system, this can be a big cost savings. As an example, a recent customer bought only the PBX from us, electing to keep the IP phones they had purchased for use with a hosted phone service, a substantial savings.
Another advantage of IP extensions is that you can plug them directly into existing network connections. Most IP phones have a built-in switch, allowing both the phone and the PC in an office to be connected to the same jack. This approach does have call quality implications however. If a PC and a phone are connected to the same network jack, and the user decides to stream hi res video while making a phone call, they may find that the audio on their call is choppy.
For existing offices with a single network jack in each office, this problem can be addressed by the use of a small network switch in each office that can prioritize voice traffic. We sell an inexpensive 5-port switch with high-priority ports.
For those building out new space or planning a major remodel, now is the time to plan for optimal cabling for IP phones. Ideally, each office should have a network jack for a PC, and one for an IP phone. This allows IP phones to be on a spearate network, maximizing performance and call quality.
If you are building new space but want to stick with digital or analog phones for the time being, I suggest you do what I have recommended to my cabling customers. Install a jack for each digital or analog phone using cat-5 cable, and terminate them appropriate to the existing phones. Later, when you want to switch to IP phones, it is a simple matter to have those cables re-terminated to cat-5. The cost differential between cat-3 and cat5 cable is minimal.