particular the Telemanagement Forum (TMF), organise many of these conferences. Some TMF initiatives will be discussed in this book. 2.2.3 Customer Management Customer management encompasses the management of charging information and subscription management. These functions include: Provisioning and termination of services according to new and expiring subscriptions; and Customised services, which are particularly sold to corporate customers. Sales staff communicate with a customer database from which instructions to the OSS are generated. The OSS then carries out the work needed to deliver services by sending commands to the software installed at the local exchanges. For example, a command might be to activate a service for a new subscriber. 2.2.4 Managing Circuit-switched Networks The operation and maintenance centres that handle the element and network levels are called the Operation and Maintenance Centre (OMC) and Network Operations Centre (NOC) respectively. Any network will generally have many OMCs but may have only one NOC (Figure 2.5). Further, each OMC may be responsible for several local exchanges and use one or more OSS. The NOC is focused on network management functions such as net- work monitoring, traffic management and signalling management. The OMCs are focused on element management, the basic functioning of the exchanges, signalling and traffic management, and element mediation. OSS for Telecom Networks OSS at NOC OSS at OMC OSS at OMC Network Network Figure 2.5 Element and network management. 2.2.5 Element Management The basic functions of an OSS include: drawing network maps for the use of human staff, from the equipment database alarm management command management translation of operational commands into communication protocols. The network map gives network management staff an overall view of the network. Network maps are usually hierarchical with the highest level showing the entire net- work. The user can drill down to see details of local areas. The highest level gives a survey and also sh