Telephone circuit to control off-hook status during receipt of caller-ID signal

Claim 1

Apparatus comprising: a computer; a data access arrangement having input circuitry connected to a telephone line port and including first and second electronic switches, closure of the first electronic switch establishing an AC coupling between the input circuitry of the data access arrangement and the telephone line port and closure of the second electronic switch establishing a DC coupling between the input circuitry of the data access arrangement and the telephone line port; a modem connected to the computer and the data access arrangement; and means associated with the modem for electronically; receiving a first ring signal from the data access arrangement; after the first ring signal ceases, causing closure of the first electronic switch to connect the modem through the data access arrangement to the telephone line port during a time in which a caller ID signal is specified to be transmitted; comparing a calling telephone number received and demodulated by the modem to a list of stored telephone numbers; and only if a match is found, causing closure of the second electronic switch, the modem remaining connected through the data access arrangement to the telephone line port, to draw an off-hook current preparatory to a call being connected to the modem on the telephone line port.