Abstract: Taught herein are a hub and an audio conference system. The system comprises a plurality of operator interface devices, each operator interface device being connected to an internet protocol (IP) network, and an audio mixing and routing hub. The hub is connected to each operator interface device through a duplex internet protocol audio channel over the IP network. In use, the hub is configured to receive at least a first primary audio stream from at least one of the operator interface devices, mix the primary audio streams to produce a first mixed audio stream, and transmit the first mixed audio stream to at least one of the operator interface devices.

Abstract: Subscribers in a mobile communications system are provided with a bundle of call time each billing period, against which standard call types are rated. If, at the end of one billing period, a portion of the bundle for that billing period remains, the rating system associates the remaining portion with a bundle provided for the forthcoming billing period. In one embodiment, rating is interrupted whilst any remaining portions of the previous bundles are added to the newly-created bundles for the next period. In other embodiments, the rating system refers both to the current bundle and to a previous bundle when rating standard call types.