TRIGON ELECTRONICS, INC.

TELEPHONE ACCESS CONTROL SYSTEMS, COMPRISING A TELEPHONE HANDSET AND KEYPAD, AN INTERCOM UNIT, COMPUTER HARDWARE AND OPERATIONAL SOFTWARE, AND ELECTRONIC CIRCUITRY FOR ESTABLISHING COMMUNICATION BETWEEN THE INTERCOM UNIT AND A REMOTE TELEPHONE, USED TO RESTRICT ENTRY TO CONTROLLED ENVIRONMENTS SUCH AS RESIDENTIAL, COMMERCIAL, AND INDUSTRIAL PROPERTIES