With all the hype about IP Centrex, you'd think that every business in American had switched to IP telephony. Analyst firm Ovum estimates that IP Centrex and hosted VoIP revenues will amount to around US $6.6 billion worldwide by 2008, up from US $255 million this year. Frost & Sullivan puts a US $7.9 billion valuation on the market by 2009. It expects, conservatively, that IP Centrex will account for at least 15 percent of all business lines by the turn of the decade, double the size of the current Centrex market.

Many end-users no longer want to have the headache of managing the PBX and its services, and service providers can manage these devices remotely on behalf of customers. This reduces the burden on the IT function within the company and, with financing deals, can even reduce capital expenditure.

How do you know if IP Centrex is right for your company? It's not just about the money, but rather how the features, functionality, and system control play a significant role in making the right choice. It can be relatively risk free - assuming the service provider can provide adequate service and accurate billing along with all those IP benefits. And as businesses view data as an equally essential method of communications and see their workplaces becoming virtual entities, stretched across multiple locations, IP Centrex becomes more desirable than ever before.

One of the issues with IP Centrex is the IP billing capability of the provider. Every outsourced telecom provider should be able to offer:

-- Bucket billing plans (like cellular billing)
-- Unlimited billing rates or plans
-- Taxes (up to 10 levels)
-- Real-time or web based call reports for end users
-- Staggered billing
-- QuickBooks Interface
-- -- Cost & Charge - Basic Cost Allocation/Billing Software Module
-- -- Billing of one-time and recurring charges

If you are considering an IP Centrex system, make sure your provider has all the call accounting and IP Billing systems in place.