Data access arrangement for detecting the hook status of an extension device

DETAILED DESCRIPTION The present invention provides methods and apparatus for interfacing a phone device with a telephone network in a manner which overcomes many of the shortcomings of the prior art.
In accordance with a preferred embodiment of the present invention, a DAA circuit is provided which detects when an extension telephone device goes off hook while the modem associated with the DAA is on hook, as well as detecting when the extension device goes back on hook.
The ability of the subject DAA to detect when an extension device goes back on hook is particularly important, inasmuch as it permits a facsimile or other data packet which is desired to be transmitted to be queued and transmitted from the queue once the extension telephone device goes back on hook.
In accordance with a further aspect of the present invention, when the modem with which the DAA is associated is in the off hook condition, the DAA is configured to detect when an extension telephone device goes off hook, and to report this event to the user of the PC to which the modem is associated.
In this way, the user can be informed that the modem connection has been terminated because of an extension off hook condition, as opposed to other common causes for modem disconnections, including internet service provider (ISP) failure, line failure, local hard drive failure, or the like.
In accordance with a further aspect of the present invention, when the modem is in the off hook condition, its associated DAA may be configured to detect when a remote telephone device (ie.
, the telephone device from which an incoming telephone call has been placed) is hung up.
This permits a modem, for example operating in the TAM mode, to terminate the connection when the remote telephone device hangs up, thus avoiding the familiar but annoying dial tone which is often inadvertently replayed by many TAM users when checking their telephone messages, as a result of the recording device associated with the answering machine commencing its recording sequence immediately before the calling party hangs up