1. How many lines are needed?

This is a key feature of every IP Phone (News - Alert) as the maximum number of available lines that a phone has will determine the maximum number of calls that a user can handle at one time. While the average office worker will likely only need one or two lines, heavy users such as executive administrators, receptionists or call center operators may need five or more.

2. What size and type of screen is required?

Besides the actual size of the screen, displays are basically either monochrome or color with some being backlit. The pixel count is important as this can give the text and any graphics a much sharper look and make them easier to read or view. Higher end phones often come with a touch screen option that can make menu navigation easier. For a basic user, a small screen should more than suffice, while people that require frequent access to a broader range of features, will likely benefit greatly from having a larger color display, such as that on the Yealink (News - Alert) SIP-T46G and SIP-T48G (Touch Screen).

A video phone such as the Yealink VP530 is often an efficient solution and worth consideration by users that benefit from frequent face-to-face communication.

3. How will the phone be used?

Different jobs will require a different set of features from a phone. These can often be broken down into different buckets such as executives, managers, office workers, receptionists, administrators, call centers, conference rooms and common areas. Given a choice, most executives would likely choose a higher end model that offers the functionality that they need to be as effective as possible. Features such as Bluetooth may be critical in addition to the ability to highly customize the device.

At the other end of the scale, a lower end model is likely a very good choice for common areas of a building such as break rooms, as the most frequent use is most likely extension to extension or outbound calling.

Some workers may need to be constantly walking around a campus while still requiring access to their phone. A good choice for this type of employee could be a wireless VoIP phone such as the Yealink DECT W52P.

4. What features and functionality are required?

A lot of the features that initially come to mind when thinking about phone features are most likely actually dependant on the capability of the phone system or hosted service. These are features such as call hold, call transfer, call park, call waiting, etc. In saying that, using these features on a phone is not always intuitive and a user can be at the mercy of how well the phone menus navigate.

Features that are actually phone specific and worth evaluating are items such as Bluetooth, headset support, expansion module support, line customization, display type and size, HD voice support, XML browser support, and Gigabit support among others.

5. How does the phone look and feel?

First impressions and perception can make or break a business deal or a relationship with a client. Having a sharp looking, robust and elegant phone on your desk will impress anyone that steps into your office, and likely be an interesting talking point. Additionally, if the device is frequently used, evaluate how ergonomic it is by considering how it feels in your hands and against your ear, in addition to the spacing of the keys. Don't forget about long term reliability.

6. How will the phone be connected to the business network?

Power over Ethernet (PoE) is the most common way to power an IP phone. If the phone is not going to take advantage of PoE then ensure that a power supply is purchased with the phone.

An Ethernet port must be available at the workstation where the phone is to be situated to allow the device to connect to an internal business network, and allow the device to communicate with an IP PBX (News - Alert) or hosted VoIP solution. Find out if the connection supports Gigabit Ethernet to take advantage of faster network speeds. If there is only one Ethernet port available at the workstation, make sure the phone has two Ethernet ports as it will then  allow for a desktop computer to be connected directly to the phone for Internet access.

7. Confirm phone make and model support with your IP PBX phone system or hosted VoIP Provider.

While the majority of IP phones use the SIP protocol, there are other signaling protocols such as Lync, SCCP, H.323 and MGCP that are in use by various call management solutions. Additionally, not every SIP phone make and model is supported by every provider, which often results in manual provisioning being necessary.

Although less likely to be an issue, support of the major CODECS such as G.711 and G.729 should be confirmed.

Just remember that not every phone works with every VoIP provider or phone system, so it is critical to confirm support before making any purchase.

8. Consider purchasing the phone directly from your VoIP provider.

If your telephony solution is serviced by a hosted VoIP provider, find out if they sell IP phones and if so, which make and models are available. This is definitely worth considering as in a lot of cases the provider will provision the phone before sending it to you. The phone will then auto-provision when it is powered on in your network, and will be immediately up and running. Many providers also subsidize the cost of the phone.

9. Confirm available Internet Bandwidth (News - Alert).

If your telephony network is growing and you are adding devices as opposed to upgrading existing ones, be sure to talk to your Internet provider to confirm your current available bandwidth. Run a VoIP bandwidth test to ensure that the expected total number of concurrent calls can be supported without interruption.

10. Decide how much you want to pay for each phone.

Different makes and models of IP phones can significantly vary in price. While some entry level IP phones are typically available for under $100, some higher end, feature rich phones can easily cost a few hundred dollars. To reduce cost there is always the option of purchasing refurbished phones, or alternatively, renting the phones from certain service providers.

In summary, although it is a fairly simple process to purchase an IP phone, choosing the wrong make or model can easily cost your company thousands of dollars in wasted expenditure, in addition to lost productivity. Taking into account the aforementioned list of items should ensure that an educated decision is made resulting in identifying the best phones, with the required features, at the right price.

About the Author:
Tony Campbell is a managing partner at WhichVoIP.com, the Internet's leading source for VoIP Information and Reviews.