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SIP Phones- Best VoIP Review has written this SIP phones review for you to understand what is a SIP phone and some of the best SIP phones. There are many SIP phones to choose from so it is important that you read this SIP phones review. SIP phones!

An Internet phone is a phone that is enabled to make calls over the Internet, using either a computer with headsets and a microphone or a hardware phone. A hardware Internet phone may work either because of elements within the phone or because it is attached to other equipment and/or software that enables such calls. This article explains SIP phone basics.

What Is a SIP Phone?

Every Internet phone uses a built-in or external control protocol in order to make or receive calls over the Internet. Examples of control protocols include Skype, Skinny Client Control Protocol, and Session Initiation Protocol, or SIP. A SIP phone, is one that happens to use the SIP protocol. Note that a SIP phone is different from SIPphone, a particular proprietary SIP service package.

SIP phone can refer to software running on your computer, or on your phone, or to a hardware phone. Because the term is used in a variety of ways, often without clarification, it’s important to be careful so that if you are, for example, making a purchase or planning a system, you end up with components that do what you think they’ll do and that work together seamlessly.

Types of "SIP Phones"

There are a number of very different items for sale as "SIP Phones." This section briefly reviews some to give you an idea of what’s available.

•　 Cisco offers a "Unified SIP Phone 3911 VoIP phone." It is a corded phone designed for low to moderate usage in a shared phone in business or education setting, including retail sales settings, lobbies, manufacturing floors, and classrooms. Its features include conference calling, hold, line select, mute, redial, speakerphone, transfer, and voicemail access. The LCD display is designed to work with caller ID and call history. The phone can be powered in three different ways: locally with an optional power adapter, Power over Ethernet (PoE), or IEEE 802.3af.

•　Cisco’s SPA5___ line of phones are SIP phones for home offices and businesses, featuring from 1 to 12 voice lines, 2 Ethernet ports, and PoE support. The product line is specifically tested for interoperability with a range of VoIP equipment. It can be linked to an IP private branch exchange (PBX), hosted IP telephony service, or large-scale IP Centrex deployment.

• D-Link has DPH-541 Wireless IP Phone, which is a Wi-Fi SIP phone that enables placing and receiving VoIP calls over 802.11b or 802.11g wireless networks by means of high-speed Internet access. It is a flip phone that can be used in any place where there is wireless network access. The phone supports encryption with WEP, WPA, and WPA2, and has a color LCD screen for display of caller ID, call history, and address book information. Hold, mute, and redial are supported.

Notice that the last of these is not a dual mode phone, meaning that it does not have the capabilities of a cell phone it will not operate unless a wireless network is available (i.e., in existence, and accessible to you, either because you have paid for it, you have been given the password, or it is free to all, such as at a Wi-Fi hotspot). This means that there are locales in which this type of phone will not function.

•　There are SIP applications for the iPhone by Apple that make calls possible over the Internet in addition to the calling capabilities over the AT&T system that are a required part of the iPhone contract. Although originally blocked, iPhone SIP applications that work over wireless (but not over cellular connections), were available in the iPhone app store as of 2009. In some parts of the country, according to reports, certain SIP-based apps for iPhone even work on AT&T’s 3G network.

Sources

http://www.buy.com/retail/product.asp?sku=202806350&listingid=66517572

http://www.voipvad.com/ProductDetails.asp?ProductCode=SPA504G-vv

http://www.sipcenter.com/sip.nsf/newsview?open&type=News&docid=WEBB7YUL7G

http://blog.tmcnet.com/blog/tom-keating/voip/siphon-sip-app-for-iphone-works-over-atts-3g-network-holy-toledo.asp

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