26.4 MB (2.8 MB compressed)
3665 x 2516 pixels
31.0 x 21.3 cm ⏐ 12.2 x 8.4 in (300dpi)
JOHN GREIM / SCIENCE PHOTO LIBRARY JOHN GREIM / SCIENCE PHOTO LIBRARY
Circuitry at telephone exchange. Clusters of telephone wires between circuit boards at a telephone exchange. Most modern exchanges use solid-state devices to carry out the switching process, with computers to control the operation.
Model release not required. Property release not required.