SB-100
Control Switchboard SB-100/MTC was semiautomatic equipment used for quickly grouping field telephones of a network for alerts, conferences, and instructions. It was usually mounted atop the administrative switchboard.
This equipment, consisting of the switchboard component and a handset, had no means for ringing and signaling.
Reference File
- TM 11-2133 Control Switchboard SB-100/MTC, 10 May 1951