- Model: wall switchboard phone
- Made by: Viaduct Manufacturing Co.
- From: 1890s
- Courtesy of: Tom Adams
This Viaduct wall switchboard looks to have six 'drops' (the silver plates on the lower box), meaning it had a six line switching capacity. The Viaduct Manufacturing Company was based in Elk Ridge, Maryland, and the company name came from the brick viaduct that had to be built next to the company's plant to support the B&O railroad tracks.