TELEPHONE ANSWERING SERVICE SYSTEMS, COMPRISING, LINE CONCENTRATOR(S) OR DIRECT INWARD DIAL IDENTIFICATION UNIT(S), DATA BASE, OPERATOR COMMAND KEYPAD OR KEYBOARD, AND OPERATOR VIDEO TERMINAL; EQUIPMENT FOR USE WITH TELEPHONE ANSWERING SERVICE SYSTEMS, COMPRISING, LINE CONCENTRATOR(S) AND DIRECT INWARD DIAL IDENTIFICATION UNIT(S); SERIAL COMMUNICATIONS CONTROLLERS; MEMORY BOARDS; INTERFACES FOR DISK DRIVES WITH COMMUNICATIONS CHANNELS; VIDEO CONTROLLERS PROVIDING PROGRAMMABLE MULTIPLE CHANNEL...

PROVIDING TELEPHONE ANSWERING SYSTEM MAINTENANCE SERVICES FOR OTHERS