A network service controller 305 has a control channel 307 by means of which the activity level of the stations 301, 303 participating in a multimedia conference call is monitored 309. Parameters monitored to determine activity include station identities, activity status of transmitting and receiving stations, transmission mode and quantity of information exchanged, duration of use, and other parameters such as prioritized conferencing information. The monitored level of activity is compared 315 with information in a history file 325 to determine if any changes have taken place, such as number of participating stations, mode or duration of transmission. If a change is detected, the history file 325 is updated.; An activity list is created 323 as a prioritized compilation of each stations present status, prioritization being based on priority station or user status, priority conferencing traffic, or increased bandwidth requirements. If a check 327 reveals that activity has increased, bandwidth resources must be reallocated and this most often involves changing the bit rate of various multimedia modes used by various stations. If activity has not increased but a second check 331 reveals that a transmitting station has exceeded its predetermined transmit time or other resource parameters, resources must again be reallocated. Thus, the bandwidth of a station that has exceeded its network parameter limit must be adjusted. If a station is not using certain resources, eg. its audio capabilities, the bandwidth used for the latter can be reassigned to another station having priority.; Bandwidth reductions may also be effected by reducing resolution or update rate of video blocks, eliminating textual or graphics capabilities or any combination of these. Stations may be linked via wires, radio or infrared.