The present invention provides a telephony-accessed application system for providing a service, such as voicemail, in accordance with a switching interface such as in the ITU-T H.323 or IETF SIP recommendation. Queuing functionality is made possible in a system which employs a switch which does not support queuing. The queuing functionality is made possible by a queue means which is provided within an application means, i.e. the voicemail means itself. Consequently, the switch itself is relieved of the burden of having to keep track of the exact status of each of its ports at all times. The high-level queuing is performed at a logical level rather than at the physical level, and therefore affords a cleaner interface. Furthermore, the implementation of the queuing functions in the terminating application means allows for the use of a wider variety of intermediate switch means in a network.