It is hard to imagine that even the stalwart, -traditional landline phone system would eventually succumb to change. On the other hand, in the dynamic environment spawned by the 21st century’s wave of telecom innovation, it stands to reason that nothing is above the fray.

It is already well established that cell phones are rendering landlines obsolete at home. The Internet is now driving a similar trend at the office.

According to two reports recently published by the Scottsdale, Ariz.-based market research firm, In-Stat, office environments increasingly are migrating to voice over Internet protocol (VoIP) in whole or in part. The change is taking place in the public and private sectors.

According to the survey, “Business VoIP Overview by Vertical Industry,” 48 percent of respondents in the government sector report that VoIP is deployed in at least one location.

While VoIP’s appeal appears to be universal, the reasons vary from sector to sector. For example, integration appears to be the primary attraction to government enterprises. Government industry respondents to the survey cited scalable features and capabilities as their most important considerations. In contrast, respondents in the education sector gave greater weight to the cost savings with VoIP systems.

While VoIP adoption in U.S. businesses is only slightly less than it is in the government sector, that will soon change dramatically. In its second study, “U.S. Business VoIP Overview: Optimization Trumps Expansion,” In-Stat projects VoIP penetration in the business sector to nearly double from 42 percent at the end of 2009 to 79 percent by 2013.

According to the report, hosted IP Centrex has now surpassed broadband IP telephony as the leading revenue-generating, carrier-based business VoIP solution. However, broadband IP telephony revenues continue to grow and will more than double by 2013, compared to 2008. This growth will be fueled by single-user applications among increasingly distributed and mobile work forces.