Abstract: An Internet Call Waiting Device (ICW) detects a Call Waiting signal even when a modem is currently using the phone line. Upon sensing the Call Waiting signal, the internet Call Waiting device alerts the user using one or more flashing lights and/or generating audible signals that the user can hear. If the user has a Call Waiting-Caller ID service the caller's name and number are also displayed if it is available from the phone company. After being notified, the user can choose to ignore the call or take the call by picking up a telephone. If the user picks up the telephone, the ICW signals the central office to put the first modem connection on hold. A connection is then made with the second call. When the second call is completed and the user hangs up the telephone for the second call, the ICW signals the central office to reconnect the first modem call. The ICW includes a signal detector for detecting a Call Waiting or Call Waiting-Caller ID signal on the phone line.

Abstract: A VMWI (Visual Message Waiting Indicator) multisense detection device solves both the problem of long CLASS VMWI signal retransmission delays and unreliable CLASS VMWI signal transmission by simultaneously enabling both stutter dial tone detection and CLASS VMWI signal detection. The multisense device samples the line each time the phone is placed on-hook or after the phone goes unanswered after a ring. If a valid CLASS VMWI signal is detected before the scheduled dial tone test, the dial tone test will be canceled. If no CLASS VMWI signal is detected, after a given amount of time, the VMWI device automatically enables stutter dial tone detection. The detection circuitry periodically polls for a preamble field of the CLASS signal to determine whether a valid CLASS signal is about to be transmitted. If the preamble indicates a CLASS signal is being transmitted, the detection circuitry remains on and the CLASS signal is received and processed.

Abstract: A simple and inexpensive telephone exclusion or privacy device. A conference feature is and am indicator light showing when the line is in use are also provided. The basic exclusion or privacy circuit includes only eleven components, thereby providing a very low cost device. The circuit includes a diode bridge with a Silicon Controlled Rectifier (SCR) connected across the midpoint of the bridge circuit. A resistor in series with the SCR limits the amount of current which the SCR can draw from the telephone line. A Zener diode in series with a resistor is connected between the anode and the gate of the SCR and a resistor in series with a capacitor is connected from the gate of the SCR to the second side of the bridge circuit i.e. to the point where the cathode of the SCR is connected.