y European ones. With the Chinese, there is a clear difference in the scale of operations, but this does not seem to influence the evolution of the software development activities. The CSPs in mainland China seem to follow the pattern without major deviations. They gradually abandon in-house software development and look for external vendors to provide the solutions they need. The CSPs in Taiwan seem to divert to an extent from the suggested evolution pattern in a similar way the European middle-sized companies do. The availability or need of some resources seems to lead to this: Maintenance of legacy software requires some work. There are still bespoken systems for which the maintenance expertise might not be easy to find. Since staff with development skills is available for maintenance tasks, that human resource is used also for some application development. Further, it is important to retain knowledge on architectures and processes in-house to ensure competitiveness in the future. The special feature of the Taiwanese telecom market is the important role of a call center. All operators invest a large portion of their resources into it (e.g., one of them has 100 people in their call center). This is also an activity they would not like to outsource. There was some interest in retaining software development as part of the business: one of the Taiwanese operators has initiated discussions about selling some systems to other South-East Asia countries, such as Vietnam and Myanmar. In the quantitative studies conducted, it was found that the large European and North American operators also still use a significant amount of resources to software development - the reasons for this can not be read, however, directly in the data. M. Pulkkinen and J. Veijalainen For those operators that have outsourced software development, there clearly is a threshold to go back into developing software in-house. These very large Chinese or small European ones in the group of studied operators are likely to be a market for different prov