Operations Support Systems (also called Operational Support Systems or OSS) are computer systems used by telecommunications service providers. The term OSS most frequently describes "network systems" dealing with the telecom network itself, supporting processes such as maintaining network inventory, provisioning services, configuring network components, and managing faults. The complementary term Business Support Systems or BSS is a newer term and typically refers to "business systems" dealing with customers, supporting processes such as taking orders, processing bills, and collecting payments. The two systems together are often abbreviated BSS/OSS or simply B/OSS.
The term OSS was historically used to include both network and business systems. It is still sometimes used in this sense, which can cause some confusion. When used in this way, the term OSS may be seen as inclusive of BSS.
Reference:
http://en.wikipedia.org/wiki/Operational_Support_Systems
