When a business goes to Voice over Internet Protocol (VoIP) for its phone system, getting phones is easy. Session Initiation Protocol, or SIP, is the standard for connecting to the network, and nearly all phones on Internet Protocol (IP) networks use it. They connect to the local area network (LAN) or to a separate VoIP network using CAT5 or CAT6 cables and an RJ-45 Ethernet connector — in other words, exactly the same way a computer does.

SIP phones look like regular phones, except that they have extra buttons for the variety of functions that VoIP offers, such as call forwarding, conferencing, and speed dialing. SIP supports video as well as voice calls, so some phones have screens and cameras for video calling. Video calls are possible on the local network, or to remote VoIP phones through SIP trunking.

Some models use Power over Ethernet (PoE) and don't need a separate power cord, saving a bit of clutter, but then the network needs power-sourcing equipment with enough watts to handle all the phones connected to it. Phones with separate power adapters are generally cheaper.

It isn't actually necessary to have a separate piece of hardware for a phone. SIP is just a protocol for real-time voice and video conversations, so any computer with a microphone, a speaker or headset, and appropriate software can serve. Another way to look at it is that a SIP phone is a dedicated computer for making phone calls.

A VoIP gateway connects SIP phones either to the public switched telephone network (PSTN) or to a service provider's SIP trunk. Both ways allow assignment of phone numbers with direct inward dialing from the public network. Similarly, a computer acting as a SIP phone can have direct inward dialing.

SIP phones are all compatible with one another, but they vary greatly in features and pricing.

For more information about which SIP phones are ideal for your business, contact TelWare at 1-800-637-3148 or TelWare is a national leader in the installation of voice, video, data and unified communication solutions. TelWare is an authorized Avaya, Star2Star and SimpleWAN dealer.

Back to News