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Types of PBX Phone Systems

Updated: Mar 15, 2021

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Types of PBX Phone Systems

Types of PBX Phone Systems

There are 3 basic types of Small Business Phone Systems. Traditional, VoIP, and Hosted:

Traditional: This is your old PBX or KSU (Key System Unit). Analog/Digital Phone Side (not VoIP) and Analog/Digital (not VoIP) Trunk Side. You will see a lot of old AT&T Merlin, Panasonic, NEC, Nortel Meridians still in use. A Traditional PBX could also use a T1-PRI if they were really advanced. These were the original Multi-Line Phone Systems.

VoIP PBX: VoIP on the Phone Side and Analog/Digital/VoIP on the Trunk Side. The typical knock on VoIP PBX Systems is that they are very expensive, both to buy and to maintain. Typically, they have been (stay tuned). See prior Phone and Trunk Side explanations, enough said.

Hosted PBX: Another type of VoIP phone system that you see in many small businesses is a Hosted PBX. A Hosted PBX is a PBX that runs on a server somewhere on the Internet. The Phone Side extends down to you on an Internet access connection. The Trunk Side and the PBX itself are owned and controlled by an external server and network.

In theory, and often, it works. But because there is so much signaling and coordination that goes on in the Phone Side, sometimes it doesn’t work so well.

At times, an IP connection can have frequent delays or latency (that don’t always come down to bandwidth) and sometimes it can cause all that Phone Side coordination between VoIP devices to slip or mis-align. Many small business customers do experience dropped and poor quality calls because they simply do not have good synchronization between VoIP devices. For some customers this is a non-issue (they don’t rely that heavily on their phones), for some businesses it just isn’t acceptable. Some questions that come into play here are simply how does phone traffic pertain to your daily small business operations, is it critical? “If the internet goes down, can I wait for my phones to come back up with it or… if this install doesn’t work, how hard will it be to switch service providers?”

Having your phone company own (not just your Trunk Side services) but your entire PBX means you are as locked as a cell phone to a cell contract.

Many times hosted-system providers advertise no contracts simply because they know they won’t need one knowing how difficult it will be for a customer to change to another service provider.

Again, it’s not that hosted-systems don’t work but they don’t work as often as a sales rep drawing a cloud would have you believe. I know this for a fact as we replace many hosted systems where the small business owner is beyond frustrated with the service. No doubt, the technology will improve over time. Be that as it may, as the Internet overall becomes more crowded with streaming other services (Netflix makes up 33% of all internet traffic), the more the voice will have to contend for on the Phone Side of Hosted Systems. Still, I’ve yet to hear one customer rave about how good their Hosted PBX works, usually their response is negative or it works “just ok”.

The proper way to design a hosted service would be with a private line circuit to the premises but then cost starts becoming a factor. Hosted Systems can also be very expensive. Because they serve you on the Phone Side, often they want per phone per seat monthly licensing. Once more it brings up more practical business related questions like “this might be ok up to 5 phones, do I see myself moving beyond that. And if I think I will be at 20 phones in 1-2 years, how much is 20 x the per seat license?” Monthly it can add up to a lot and again, it may not be very easy for you to change phone systems once the time comes. Some forethought now could save you some much-needed growth capital later on.

Understanding the PBX nature of Phone and Trunk side and how VoIP applies to each individually, in addition to knowing the different type of phone systems available, will go a long way towards helping you plan your future phone system needs.


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