Patent ID: 7412035

Claim:
A method comprising: placing a preliminary test call to a telephone line over a network; in response to the preliminary test call, receiving first signaling data through the network; evaluating the first signaling data to determine whether a busy or disconnect signal is received from the network in response to the preliminary test call; if it is determined that the busy or disconnect signal is not received in response to the preliminary test call, placing a follow-up test call to the telephone line, the follow-up test call being placed while the preliminary test call remains connected; in response to the follow-up test call, receiving second signaling data though the network; evaluating the second signaling data to determine whether a busy or disconnect signal is received from the network in response to the follow-up test call; and if it is determined that the busy or disconnect signal is not received in response to the follow-up test call, concluding that the telephone line has an optional telephone service enabled.