One embodiment disclosed relates to a modular apparatus for telecommunications services. The apparatus includes at least a network interface, a service logic program, and a plug-in module. The network interface exchanges signals with a telephony network, and the service logic program communicates control events with the telephony network by way of the network interface. The plug-in module is configured to exchange in real-time (i) a first type of messages with a charging server and (ii) a second type of messages with the service logic program.