Patents by Inventor Shawn E. Carlson

Shawn E. Carlson has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5278895
    Abstract: A voice message system for a pay phone telephone network interposes an Intercept Processing Subsystem (IPS) in the line connections between the pay telephones and the central office. A Voice Processing Subsystem (VPS) is connected to the central office switch by a trunk. A caller at a pay station enters a called telephone number which is stored in the IPS. The Intercept Processing Subsystem monitors the line connection to determine if the called telephone remains on-hook for a predetermined number of ring tones or is busy for a predetermined number of busy tones. If the ring no answer or busy condition maintains, the IPS reduces the volume of the ring or busy tones on the line connection and superimposes a voice announcement thereon offering the voice message service to the caller. If the caller enters an acceptance key sequence or coin deposit, the IPS splits the line connection, sends a Thank You message to the calling telephone and speed dials the VPS.
    Type: Grant
    Filed: November 22, 1991
    Date of Patent: January 11, 1994
    Assignee: Unisys Corporation
    Inventor: Shawn E. Carlson