Also referred to as IP Phones, SIP (session initiation protocol) phones are phones that are specifically designed to use with VoIP. Most of the SIP phones have ATA already installed, so connecting them to a computer is not necessary. Just like telephones, SIP phones are available in both wired and wireless versions.

You can connect these phones to your LAN or ADSL internet router very easily. They are quite convenient and some models also come with Ethernet ports which means you can plug RJ-45 cables into them so that you can enable LAN connections. Doing this connects them to the internet via the server’s router. Furthermore, the RJ-45 port also works as a power source for the phone, so you won’t have to plug it into an electrical outlet. Depending on your preference, you can also use the RJ-11 port to connect the phone directly to the router so that it may work on a conventional PSTN line.

Just as a wide range of different models are available of cell phones and conventional phones, SIP phones also have many different types. They range from basic models that have limited features to the advanced ones that are equipped with latest technology and allow you to use them to surf the web or use them for video conference.

There are a few features that you should look for in a SIP phone when you are about to buy one. First and foremost, it should support IP protocol, obviously, it is also known as TCP/IP. Apart from this, you should also make sure that it has a RJ-45 port as it will allow you to connect it to a LAN. An RJ-45 port is similar in appearance to the port for a conventional connection on an old landline, although it is bigger in size. Furthermore, having a keypad is also essential so that you can dial numbers to call people. It is also recommended that you get the one that has an ATA internally installed. Keep in mind that if a SIP phone is labelled “IP-enabled” then it means it does not have ATA and you will have to some more money and time to set it up. So, avoid the hassle by simply purchasing the one that has an internally installed ATA.

A wireless SIP phone would be a good choice for you if you move around a lot. By connecting to a wireless LAN, these phones let you move around while making or receiving VoIP calls, without being tethered to a certain spot. Wireless SIP phones can also be used in Wi-Fi hotspots if you aren't always at home or in the office. Wireless IP phones are costlier than the wired versions, but the convenience and freedom they offer are worth the additional cost.

Although their price tag might deter some people, it is worth mentioning that a good quality SIP phone costs less than what you would spend for a good quality cell phone or smartphone.