 they have also outsourced software development and maintenance to the newly emerging OSS/BSS software industry. Sanz et al. (2006) from IBM note that telecommunications operators have modularized their operations in the form of an agreement on the enhanced telecom operations map. This modularization and standardization of operations is the result of telecom operators' willingness to exploit the economies of scale arising from external providers supplying software to the telecom operators' common needs. Our interviews with six telecommunications operators and four OSS/BSS vendors in Europe indicate that, until approximately the 1980s, voice services over fixed telephone lines were the only ones provided by the CSPs to their customers. The operators were mainly national incumbent firms or state agencies to begin with. All the operations for providing these services were conducted within L. Frank (X) Department of Computer Science & IS, University of Jyväskylä, P.O. Box 35, 40014, Finland e-mail: Lauri.Frank@jyu.fr P. Tyrväinen and O. Mazhelis (eds.), Vertical Software Industry Evolution, Contributions to Management Science, DOI 10.1007/978-3-7908-2352-3_9, C Springer-Verlag Berlin Heidelberg 2009 L. Frank et al. the CSP and thus were vertically integrated. The needed operations software (OSS) was developed within the CSP, unless it came with hardware equipment such as with some switchboard solutions by companies like Ericsson and Siemens. In the 1990s, the situation changed: on one hand, the regulation was rescinded and the markets were liberalized, and on the other, new communications technol- logies emerged and were added to the CSP's service offering list. Besides voice communications, CSPs now started to provide, for example, broadband internet connections and mobile communications services. It should be noted that each of the services was usually operating on the top of its own specific network technology and its own OSS/BSS. Later on, some of the OSS/BSSs have been unified across the CSP's services. For exam