No one likes to wait long when the telephone is out of order. Maintaining customer telephones is a significant problem for telephone operating companies because delays in fixing troubles mean dissatisfied customers. Moreover, the high costs of maintenance adversely affect the profits of the telephone companies. Within NYNEX (a regional Bell operating company and the parent company of New York Telephone and New England Telephone), improving the maintenance process is a strategic priority. The problem of diagnosing and fixing customer-reported telephone troubles has been made more difficult in recent years by the proliferation of new kinds of customer premise equipment, such as answering machines and cheap telephones, nonstandard equipment that was not anticipated by the diagnostic systems designed during the predivestiture days of the Bell System. The goals of improved maintenance are: a shorter time to diagnose and fix a trouble; fewer handoffs from one person to another when analyzing and repairing the trouble; a reduction in repeat complaints-- complaints that resurface after the trouble was cleared; a reduction in false dispatches--the sending out of a repair technician when the problem is actually in the customer premise equipment, or there is no trouble found at all; and a reduction in double dispatches--the sending out of a repair technician to the home when the problem is in the cable, the central office, or some permutation of these locations. Customer troubles are currently recorded by a Centralized Repair Service Answering Bureau (CRSAB) that answers calls to 611.1 The troubles are then screened in a maintenance center where they are diagnosed by maintenance administrators, who then dispatch the troubles to technicians in the field or the central office. The maintenance administrator first diagnoses where the trouble is: the customer premise equipment, the customer’s wiring, the cable facilities (underground or aerial), or the central office (switch, frame, or program control).2 If the trouble is in customer premise equipment, the maintenance administrator can talk with the customer to help diagnose the trouble. The entire operation runs on 1970s-style automation: A mainframe computer system, the loop maintenance operation system (lmos), which was introduced by AT&T in the early 1970s, replaced an earlier operation based on paper slips and dispatch wheels. The CRSAB clerks enter the troubles into lmos; the maintenance administrators receive the troubles from lmos and dispatch them through lmos to the field technicians; the technicians receive their assignments on hand-held lmos terminals and enter the final status of the troubles back into lmos.