Integration with traditional PBX
The first thing that you should consider when purchasing an IP PBX is whether or not the IP PBX that you are considering purchasing will integrate with a traditional PBX. This is an important consideration even if you are planning on replacing your traditional PBX.
Think about it for a moment. If you disconnect your existing PBX, and then start setting up your IP PBX, the company will be without phone service until the new PBX is brought online and configured. You can prevent an interruption of service by adding the new IP PBX to the existing PBX system, and then gradually moving things over to the new system.
In my opinion, the most important consideration when purchasing a PBX is reliability. After all, the phones are something that everyone expects to always work. If e-mail goes down, the first thing that people often do is to reach for the phone instead. As such, it is important to make sure that the IP PBX that you choose can deliver the reliability that people have come to expect. Besides, nobody wants to have to explain to the CEO why he can't get a dial tone, or why his call was cut off.
There are two main things that you can do to gauge the reliability of an IP PBX system. One thing that you can do is to look for reviews online. Computer geeks are notorious for blogging about hardware and software, and the odds are really good that you can find someone who has already deployed the IP PBX that you are considering purchasing. A blog entry will often tell you how the product is performing, but it may also offer some hints about getting past some of the more tricky configuration issues.
Another important way to gauge an IP PBX system's reliability is to look for features that make it reliable. For example, does the unit that you are considering provide automatic failover for voice clients? Is there another mechanism for establishing connectivity to the PSTN if your primary WAN connection fails?
Once your IP PBX is up and running, you probably won't need a lot of support, but a PBX system is such a critical component of a company's infrastructure that you need to make sure that top-notch support is available whenever you need it. Therefore, it makes sense to verify that the company's support line is available 24 hours a day.
You should also make sure that the people working the support line are efficient and understandable. If I am calling a technical support line, it means that I have a problem that I need to resolve quickly. If the person working the tech support line is confusing to me, then it will take much longer to get the problem fixed.
While I am on the subject of support, be sure to check into the cost of the support. Some providers charge a fee for each support incident, while others offer annual support contracts.
It is important to make sure that the IP PBX that you choose offers the features that you need, but don't get too hung up on choosing the product with the most features. It has been my experience that as a company's competitors offer more features, then a company will soon offer those same features to their customers through a firmware update.
Another important criteria for choosing an IP PBX is the operating system that the unit uses. If you need to be able to customize the PBX software, then you will probably want to check into a Linux-based PBX that uses open source software. On the other hand, if your network is 100% Windows based, then you may be reluctant to bring in a Linux PBX, and might be happier investing in a Windows-based PBX.
Another consideration when picking out an IP PBX is whether or not the manufacturer offers any kind of training. Don't expect your IT staff to just automatically know how to implement an IP PBX. Adding VoIP to a network requires a specialized set of skills, and the proper training is essential. You should consider the cost of training when determining the total purchase price.
Is your network ready?
Regardless of which PBX system you ultimately decide to purchase, you need to take a good, long, hard look at your network. Working in the field, I have seen a whole lot of poorly designed networks. In most cases, an inefficient design won't keep a network from working (although this isn't true in extreme cases). I have seen some really badly designed networks that were still perfectly capable of facilitating file transfers, e-mail, etc.
The problem is that VoIP requires a lot more bandwidth than data does. Adding an IP-based PBX to a poorly designed network has the potential to be disastrous. VoIP calls may become completely unreliable because the network is unable to deliver sufficient bandwidth, and data transfers may slow to a crawl. As such, I highly recommend making sure that your network is up to the job before you even consider purchasing an IP PBX.
About the author
Brien M. Posey, MCSE, is a Microsoft Most Valuable Professional for his work with Windows 2000 Server and IIS. Brien has served as CIO for a nationwide chain of hospitals and was once in charge of IT security for Fort Knox. As a freelance technical writer, he has written for Microsoft, CNET, ZDNet, TechTarget, MSD2D, Relevant Technologies and other technology companies. You can visit Brien's personal Web site at www.brienposey.com.
This was first published in October 2007