Complex sentence: As manager of the Universal Service Fund, the USAC oversees the contributions received from all companies providing interstate and international telephone service, including Voice over Internet Protocol (VoIP) service, which the USAC categorizes as interstate calling.
Split into simpler sentences: As manager of the Universal Service Fund, the USAC oversees the contributions of received from all companies providing interstate and international telephone service. This has since been expanded to include companies providing Voice over Internet Protocol (VoIP) service, which has been deemed interstate calling.