GE Speedtronic Mark IV DS3820RTDB is an RTD Input Module and functions as an RTD Board. Temperature is measured by RTDs, or resistance temperature detectors, which have a ceramic or glass core wrapped in fine wire and protected by an outer casing. This board is held in place by two downward flanges and one upward turned flange on a metal carrier. Each corner of the carrier is factory drilled and tagged with the board's id number. Two vertical pin connectors and a number of capacitors are included on the circuit board.
The RTD components are also included. The board surface has a waffle design printed on it and is drilled twice in each corner for mounting possibilities. The circuit board was connected to the carrier surface using four of these drill sites.