JOHNSON CONTROLS CARDKEY CK721 A NETWORK CONTROLLER 27-5379-714 BROKEN FROM SIDE
The CK721-A is a critical, field-installed network controller designed for Cardkey’s high-security access control systems (typically part of the System 721 or similar legacy series). It acts as the intelligent intermediary between a central host computer/server running the access control software and the downstream door hardware (readers, locks, door contacts, etc.).
- VOLTS: 24VDC
- AMPS: 24VA MAX
- FUSE: NA
Key Features & Specifications:
- Network Connectivity:Â Serves as a node on the access control system’s proprietary data network (often a RS-485 multi-drop network or similar). It communicates bi-directionally with the host PC and other controllers.
- Local Intelligence & Storage:Â Contains a microprocessor and non-volatile memory. This allows it to:
- Store a database of cardholder credentials, access levels, and time zones independently.
- Make real-time access decisions at the door without relying on a constant connection to the host PC (offline operation capability).
- Buffer transaction events (door alarms, access granted/denied) for reporting to the host.
- Hardware Interface:Â Provides multiple input/output (I/O) connections to control and monitor door hardware:
- Reader Ports:Â Typically connects to two card readers (one for each side of a door).
- Inputs (Alarm Points):Â Monitors door position contacts, request-to-exit devices, and other alarm sensors.
- Outputs (Relays):Â Controls electric locks, door strikes, and other locking mechanisms.
- Legacy System Component: This controller is part of a mature, robust product line. It is known for reliability but is considered a legacy or discontinued product. Support and integration with modern software may require specific legacy interfaces or migration paths.
- Physical Form Factor:Â Typically a beige or metal enclosure designed for mounting in a secured area (closet, above ceiling, or electrical room) near the controlled doors.
Common Applications:
- Corporate office buildings
- Government facilities
- Industrial plants and data centers
- University campuses
- Any environment requiring a hardened, intelligent access control system with offline capability.



























