Pelco M (Project 68) Protocol Files

Updated: 5:51 PM 8/11/2025
These documents describes the communications protocol used in Pelco's second generation CCTV monitoring systems. The protocol can be used in a variety of physical layer implementations. Because of the token passing mechanism of the protocol, each device must be able to hear its peers. Physical layers that have been discussed include, but are not limited to:

  1. Serial communication lines using single wire EIA-485.
  2. Modified Ethernet implementations (10 Base T, 100 Base, and Gigabit).
This protocol intentionally avoids describing a physical layer implementation.

This protocol is designed to operate a wide variety of devices. It is not designed to be specific to any particular element in a system. It is not, for example, a “keyboard protocol” or a “dome protocol”. It includes elements that will control both of these devices but is not specific to them.

The following are objects in the Millennium Architecture. A particular device may consist of one or more of these objects.

  1. Access Control
  2. Alarms
  3. Alarm Master
  4. Audio
  5. Bus Master
  6. Cameras
  7. Diagnostic Devices
  8. Enclosures
  9. HW User Interface
  10. Lenses
  11. Monitors
  12. Motion Control
  13. MUX
  14. Power Supplies
  15. Recording Equipment
  16. Relays
  17. Switch
  18. SW User Interface
  19. System Clock
  20. System Master
  21. Transmission Systems
  22. Video
  23. Video Signal Equipment
  24. 3rd Party Interface
M (Millennium or Project 68) Protocol Files
Developer's Guide to the Millennium Architecture, 10/03/2001 M Protocol AGENT, 10/19/2001 Commands, 10/03/2001
Data Base Upload/Download Commands, 11/11/2024
M Alarm Box for Project 68, 10/03/2001 M Keyboard, 10/03/2001 M GPI Box for Project 68, 10/03/2001