On January 13,1976 the Atlanta Fiber System Experiment was turned up, and 44. 7 Mb/s signals were successfully transmitted over the entire system. The following papers in this issue describe the technology employed and some of the principal results of this experiment. An experimental optical fiber (fiberguide) system has been designed by Bell Laboratories to evaluate applicability of fiberguide communications to interoffice trunking. sheathed and protected cable, containing over 100 multimode graded-index fibers, which is. in Atlanta in 1976. Although there have been a. The first commercial test of fiber-optic telecommunications took place on May 11, 1977, in downtown Chicago, marking a significant milestone in the evolution of communication technology. 25-mile-long) fiber optic cable under the streets of Atlanta, Georgia.