73653932
Apr 8, 1987
Jan 12, 1988
APPARATUS FOR CONNECTION TO A TELEPHONE PRIVATE AUTOMATIC BRANCH EXCHANGE (PABX) OR KEY TELEPHONE SWITCHING APPARATUS FOR PROVIDING ONE OR MORE FUNCTIONS OF ALTERNATE OR LEAST COST TRUNK CALL ROUTING, SPEED DIALING, TONE TO PULSE CONVERSION, PULSE TO TONE CONVERSION, TOLL TRUNK ACCESS CONTROL, DIGITAL SIGNAL SECURITY, AUTOMATIC REDIAL, AND TOLL CALL ACCOUNT REGISTRATION; TONE RECEIVERS, LOOP TO GROUND START CONVERTERS; TONE RINGERS; TONE GENERATORS; INTERCOMS, AND TONE FILTERS
Electrical and Scientific Apparatus