• TB1 - 12VDC power input connector
• TB2 - RS-485 network connector
• TB3 - NXT reader connector
• TB4 - Door sense and RTE inputs + lock relay output

1.2 PC to Network Connection

The PC is connected to the Neutron network using a USB (ATC-820) RS-485 adapter. The USB connector connects into an available USB port on the host PC and the RS-485 connection is made to any controller on the network (one PC-to-controller adapter is required per system):

1.3 Controller to Controller Connections 

1.4 RS-485 Network Wiring

This diagram illustrates an example system using the maximum 8 controllers. The USB-RS-485 adapter connects to one of the Neutron controllers and the other Neutron controllers are hard-wired together via RS-485 cable.

Notes:

• The RS-485 network should be a multi-drop daisy-chain topography. Keri recommends against using a star configuration.
• The maximum total RS-485 cable network length is 4,000 ft/1200m

1.5 Wiring an NXT Reader

Note: Recommended reader cable is Belden 8237 (or equivalent), this is a 2-pair shielded, stranded, twisted cable.

- Pin 1 - +12VDC Output (red)
- Pin 2 - Ground + shield (black)
- Pin 3 - RS-485 A/+ (green)
- Pin 4 - RS-485 B/- (white)

 1.6 Wiring an NXT Exit Reader

1.7 Request-to-Exit Input Connection

1.8 Door Contact Input Connection

1.9 Fail-Safe Lock Connection

1.10 Fail-Secure Lock Connection 

 2.0 Cable Recommendations

• Input Power - Belden 8461 - two conductor, stranded, AWG 18 wire
• NXT Readers - Belden 8723 (or equivalent) - this is a 2-pair shielded, stranded, twisted cable.
• RS-485 Network Cable - Belden 9501 - two conductor, shielded, twisted pair, stranded, AWG 24 wire or larger (note that increasing the wire gauge does not increase the total network length... The total network length is 4,000m/16,000 feet.
• Input and Output Connections - Belden 8461 - two conductor, stranded, AWG 18 wire.
  
  Note: The Lock Output relay may require a heavier gauge of wire depending upon the current demands of the lock and the length of the lock wiring run.
  
  
• USB Adapter to PC Extension Cable - A USB extension cable can be used to extend the connection between the PC and the USB adapter - this cable should be a maximum length of 20 feet.