Upgrading or Purchasing a New Business Phone Service – POTTS Formula

Upgrading or purchasing a new business phone system always seems to incorporate a balancing act between the features you need and the aspects you want.  Sometimes this also means we try to make a purchase decision based off something completely unrelated to the effect of the system on our business (like wanting the newest technology because it’s new).

We often have customers call us asking for a quote on a VoIP/SIP Trunking system, when in the end, what they actually need is something quite different.

We’ve come up with a very basic formula that covers the three important questions to ask yourself before making a decision on what type of system may be best for your company.

***Quick Disclaimer: This “formula” is merely a rudimentary guide to get you to think about 3 very important aspects of your new phone system, there are a lot of other variables that should be taken into consideration before making a purchase.  This guide is a way to point you in the right direction and give you the proper knowledge you need to start a healthy discussion with your carrier.

The POTTS Formula

The One Voice POTTS Formula stands for Price Over Tolerance Times Security. 


The three aspects of the formula: Price, Tolerance and Security are all rated on a scale of 1 – 10.


The price component of the POTTS formula is your determination for how much money you are willing to spend, overall, on your new phone system.

The scale ranges from 1 – 10:
1 – the cheapest system possible
10 – money is not an issue (within reason of course).

This needs to be an honest evaluation of your overall telecom budget – we understand that you want the best price possible for the type of service you are going to get.

Some factors to consider are:

  • New individual phones
  • Purchase of an on-premise PBX
  • Monthly maintenance
  • Human resources available


The tolerance component of our POTTS formula is your level of tolerance for reliability.  For example, some companies will not lose money if their phone service is interrupted for a few minutes, whereas other companies lose hundreds of dollars for every second their phone system is down.  We all want our systems to be working 100% of the time, but there are times when our provider or our service experiences down time. Your level of tolerance helps us determine if you need to purchase a highly reliable system.

the scale ranges from 1 – 10:
1 – No or Very Little Tolerance (we lose money if our system is offline)
10 – Very Tolerant of possible interruptions (if our service goes down, we just use our cell phones)


Security is the scaling factor of our POTTS formula.  Sometimes you may want the cheapest system possible and have an extremely high tolerance for service interruption – but if Security is an extremely important factor (maybe for HIPPA reasons) then the Security portion will scale you towards a more secure system with more control.

the scale ranges from 1 – 10:
1 – Security is of very little concern
10 – Security is absolutely vital for our systems

The thing to keep in mind with security is the difference between perceived threats and real threats.  If it’s not within regulation to transmit phone calls over the public internet, then perhaps you would rate your security a little bit higher.


Once you’ve given yourself an honest assessment of your Price, Tolerance and Security requirements, you can input those 3 numbers into your formula – which will result in your POTTS Score.

Use the following scale to determine roughly what system you might want to consider for your new purchase.

0.1 – 0.5 : Hosted VoIP / Hosted PBX Solution

0.6 – 5.0 :  SIP Trunking

6.0 – 10.0: PRI System or SIP Trunking + MPLS

 Couple of Examples

Example 1:

Let’s say we had a very minimal budget for our new system (maybe we’re a new start-up) – I will rate our Price as a 2.

Our new company doesn’t lose money at all if our phone system goes down and in fact we probably won’t really use the phones all that much (everyone in the office has cell phones and uses those for business purposes).  I will rate our Tolerance as a 10.

Security isn’t of big importance, we’re only taking calls from people that are inquiring about our service, we don’t take credit card information over the phone – so I will rate our Security as a 1.

Inputting these numbers into the formula – My resulting answer is .2

My POTTS SCORE puts me in the Hosted VoIP / Hosted PBX solution! That’s great!

Example 2:

In this example we’ll use a medium sized business that is looking to upgrade from analog phone lines.  This company is also in the medical field and has HIPPA requirements.

We understand that we’re going to need to spend some money on our new system and we’ve set aside a modest budget for it, so we’ll rate our Price as a 5.

While we don’t lose money if our system goes down, it’s relatively important for us that our customers are always able to get through to us; they may have medical concerns, billing issues, etc. So we’ll rate our Tolerance as a 5 as well.

We’re constantly dealing with HIPPA requirements and we take personal information from our customers over our phone system.  Security is of the utmost importance to us.  Our company policies do not allow us to discuss medical records or information over any communication that uses the public internet.  I would rate our Security as a 10.

Had we just used our Price and Tolerance, our POTTS SCORE would have been a 1, making us a prime candidate for SIP Trunking. However, due to our Security demands, our POTTS SCORE is actually a 10. 

My new POTTS SCORE puts us in the PRI or SIP Trunking + MPLS Category!

Wrapping It All Up

Remember, our One Voice POTTS Formula is simply a self assessment tool to get you to think about three very important factors before making your next purchase.  In the end, the system you will decide on depends greatly on many other factors of your business and how you operate (like how many employees you have, how many different locations there are, etc).

The One Voice POTTS Formula provides you with a foundation for discussion.