External detection of optional telephone services

摘要

A method to determine telephone services enabled on a telephone line that is registered to receive services from an online service provider includes determining whether a telephone line registered to receive services from an online service provider is occupied. One or more test calls are placed across a network to the telephone line conditioned upon whether the telephone line is determined to be occupied. Signalling data is received through the network in response to the test calls. One or more telephone services believed to be enabled on the telephone line are determined based on at least the signaling data.