While waiting in line to get into the rooftop clubs above Wrigley Field, for a Cubs game this past Saturday, I found this old school Western Electric Telco box. It was located a newer much more modern ATT Dmark box.
According to a posting I found on eBay, this device was officially named Western Electric 116C Telco Covered Splice Box 6 Pair.
I found this line online about what the device was used for:
“What they really are for is to keep the wiring from burning up and to provide some protection to a telephone. The breakdown voltages are pretty high as they need to let through the ringer voltage (approx 90 VAC, 20 Hz) and station battery voltage (-48 VDC).”
I believe they provided protection from lightning surges.