CEM-2020, CEM-2020H, Contact Expansion Module

Enhance your ability to satisfy large and complex logic schemes and seamlessly increase the number of contact inputs and outputs by adding the CEM-2020 to the DGC-2020, DGC-2020ES, DGC-2020HD, DECS-250, DECS-250E, DECS-250N, or the IEM-2020. Each module adds 16 inputs and up to 24 outputs that are easily programmed through BESTCOMSPlus® for easy integration into the system.

For instruction manuals, refer to the DECS-250, DECS-250E, DECS-250N, DGC-2020HD, DGC-2020ES, DGC-2020, or IEM-2020 product page.


  • The rugged, potted design of the CEM-2020 and CEM-2020H provides ultimate reliability in extreme environments.
  • Enables easy addition of contact inputs and outputs through logic, reducing the need for external control devices, saving both time and money.
  • The CEM-2020H provides contacts with a high current rating, eliminating the need for additional and expensive interposing relays, control relaying, PLCs, or other peripheral devices.
  • Connects to compatible devices via CAN bus and automatically integrates into BESTCOMSPlus® software for simple, quick configuration of complicated systems.



Technical Resources