Subseries A. Technology and Operations Records from MCI groups and departments involved in constructing, maintaining and operating MCI's transmission network, includes records related to the design and implementation of computerized switching, digital distribution and fiber optic transmission, and local distribution facilities planning and procedures. The fourth group, Locality Engineering Records, documents the everyday maintenance and development of the MCI network, through Capital Project Appropriations Requests [CPARs], technical proposals and designs, applications to the FCC for project authorization, and other correspondence and memoranda concerning project initialization, development, and status.

The 1st subgroup of Locality Engineering Records, Historical Files, is comprised of records related to the nationwide acquisition of sites for microwave towers and other transmission facilities necessary for the original routes within the MCI national network, and includes site survey data; correspondence concerning acquisition of leases and rights of way; tower and transmission path engineering data. Selected pictorial documentation of sites, particularly skyline surveys from rooftop sites in various U.S. cities and towns, has been transferred to the Pictorial Collections Department.

The 3rd subgroup of Locality Engineering Records, Selvin Completed Files, includes a number of interesting files on Fiber Optic projects, which document the particular challenges, both technical and political, of implementing MCI's transition to fiber optic transmission during the mid to late 1980s.

Subseries B. Records of Thomas Leming, Senior Vice President of Transmission Systems and later of MCI's Engineering department, documents the transformation of MCI's telecommunication network from Goeken's original vision of a single Chicago-St. Louis route to a nationwide and international integrated fiber optic, microwave and satellite system in the 1980s. Correspondence, technical reports, agreements, presentations, and supporting material (maps, equipment and construction sites photographs, etc.) present MCI's negotiations with railroad companies for right of way (ROW) access for cable installations and with vendors regarding leasing or purchasing telecommunication equipment; discussions of network construction technical problems; equipment choice, evaluation, and replacement.

Subseries C. Records of Conrad Kopala, an engineer whose career with MCI spanned more than 20 years, are concerned with the optimization of MCI telecommunication network architecture, including development, implementation and maintenance of projects directed towards the transformation of the MCI system into a modern automated network, including MECCA, SONET, SCORPIO, Intelligent Network, and RTR. Of interest are his memoranda containing summaries of notes taken at engineering staff Status Review meetings in 1984-1986, which present vivid discussions of actual technical problems faced by MCI in the competitive environment of AT&T divestiture and equal access.

Subseries D. Miscellaneous Engineering Records. Three groups of records make up this series: 1. Internal Telecommunications, correspondence and memoranda concerning design, installation and maintenance of MCI's internal telecommunication services. Steve Davidson, the circuit engineer at MCI responsible for internal service, also had some responsibility for aspects of customer orders, which records are also included here. 44 telephone equipment catalogs have been transferred to the Hagley Library Imprints Department's trade catalog collection. 2. Cellular Geographic Service Area design records, related to MCI's bid to enter the cellular telephone market in the mid-80's, and showing the process of selecting, designing and engineering cellular transmission facilities in various urban markets. 3. Network Maps. Western Union Telegraph Company maps acquired by MCI, representing WU's urban network routing, conduit locations, and cabling. Rolls of drawings are organized alphabetically by the name of the states, and by the name of the city within the state; stored in plastic bags. 1917-1993, bulk date 1920s-1950s; 105 rolled maps.