This is a category of an application service provider based in India using bulk telecom resources to service it's customer in India or outside the country. The businesses like call centers, NOC & BPOs etc. are of the kind of services, which qualify for the OSP category. The Telecom resources is Public Switched Telecom Network (PSTN), Public Land Mobile Network (PLMN), Integrated Services Digital Network (ISDN) and /or the telecom bandwidth provided by authorized telecom service provider having valid license under Indian Telegraph Act, 1885.
It is important to register every business of such category to be registered with DoT for the primary reason of internal security and prohibition of toll bypass.