Petty Officer 1st Class Whitney Stettler, 365th Training Squadron Digital Voice Switching course student inspects the telephone receiver on the DMS-100 at Sheppard Air Force Base, Texas, June 13, 2017. This course provides an introduction to major areas of digital switches for identification of telephone exchange switch equipment. ( Air Force photo by Liz H. Colunga/Released)

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Size: 4512px × 3008px
Photo credit: © AB Forces News Collection / Alamy / Afripics
License: Licensed
Model Released: No

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