By contrast, Open Source PBX systems delivered an astounding 30 percent growth during the same period.

Does the proprietary PBX market eventually recover, retain its 82 percent market share, and peacefully coexist with Open Source PBXs, which today hold the remaining 18 percent ? Increasingly it's looking like the answer could be no. Our research shows increasing evidence that Open Source and proprietary PBXs are engaged in a heated battle similar in respects to early Linux and Microsoft server wars, with the proprietary PBX giving up ground, at least for now. Over time we conclude the business model for both groups requires significant tuning.

Today several opinions converge to dissuade proprietary PBX companies from looking over their shoulder and reassessing their game plan even in the face of bold Open Source inroads. Our research shows these are among the strongest held opinions:

* Only technology companies are Open Source users

* Open Source systems in deployment are only small configurations

* Most Open Source PBXs are in test and not production environments

* Open Source PBXs do not "show up" in bid situations

Our research of over 7,000 enterprises (small through large) provides convincing evidence that these opinions are mistaken.

The report "Open Source PBX Market Size, Forecast and Analysis," published by Eastern Management, addresses these points. The question of whether Proprietary PBXs are found to compete for deals against Open Source PBXs is the subject we address in this article.

Our worldwide research finds 51 percent of companies that acquire an Open Source PBX scrutinize proprietary PBX alternatives prior to making a decision.

There are some interesting characteristics about this inquisitive group of Open Source PBX purchasers.

First, the Open Source PBX systems these customers purchase are large when compared with overall market averages. At an average of 147 station lines, they have four times the number of stations of the typical Open Source PBX. That also makes these systems 50 percent larger than the average proprietary PBX sold today. This is larger too than the average PBX sold by any of the top 10 conventional PBX companies.

Second, as businesses acquire more Open Source PBXs over time, they are more inclined to consider a proprietary PBX option. This is paradoxical. It's also an important piece of the puzzle for conventional PBX manufacturers that assess Open Source challenges. For example, companies buying their first Open Source PBX seriously look at proprietary alternatives 48 percent of the time. Those installing an Open Source PBX for the second time look at the proprietary options 53 percent of the time.

Curiously, the number of proprietary PBXs examined tends to increase with customer experience, from 2.17 proprietary PBXs evaluated by first time Open Source customers, to 2.20 for those on their second Open Source PBX. For the universe of Open Source customers, 2.24 proprietary PBXs are vetted before a business selects Open Source. This last number makes the point that the more Open Source experience gained, the more proprietary PBX options are explored.