The single door interface board enables system integrators to connect TTL (D1/D0, lock/Data) or RS-485 devices, and door hardware. It includes:

• Support for tri-state LED control and buzzer control.

• Two Form-C relay outputs for strike control or alarm signaling.

• Two supervised or unsupervised inputs for door position and request-to-exit push-button monitoring.

• 2-wire RS-485 communication with the system controller.

Single Door Interface Components

Supplying Power to the Single Door Interface

The single door interface accepts 12 or 24 VDC for power on TB2 (VIN and GND).

• Locate the power source as close to the MR50-S4 as possible.

• Use a minimum of 18 AWG wire.

Communication Wiring

The single door interface communicates with a controller over a half-duplex, multi-drop
2-wire RS-485 interface. The total cable length supports up to 4,000 feet (1,219 meters).
Use a twisted-pair cable (minimum 24 AWG) with drain wire and shield. See single door interface specifications.

Reader Wiring

The reader port supports a reader with TTL (D1/D0, Clock/Data) or 2-wire RS-485 signaling. Use the following cable types:

• TTL (Wiegand): 6-conductor (18 AWG)

• RS-485: 4-conductor twisted pair (24 AWG, 120Ω, shielded). Use one pair for data and one pair for power

Power to the readers is 12 V DC, 600 mA maximum per reader port. Readers that require different voltage or have high current requirements must be powered separately with a common ground. Refer to the reader manufacturer specifications for cabling requirements. In the 2-wire LED mode the buzzer output is used to drive the second LED. Reader port configuration is set via the host software.

J602 Reader Port Termination

The J602 jumper is located next to the reader port and controls OSDP termination. This jumper should be set to the ON position when using an OSDP reader. Set the jumper to the OFF position when using a non-OSDP reader.

Reader Wiring Diagrams

Alarm Contact and Cabinet Tamper Input Wiring

The single door interface requires filtered 12 to 24 V DC ± 10% for power. Two inputs are typically used for door contact and exit push button monitoring. End of line resistors are required for input supervision, shown below.

Control Output Wiring

The single door interface provides two Form-C relay contacts for controlling door strikes or other connected devices. When switching loads, especially inductive loads such as strikes, abnormal contact wear and premature contact failure can occur. Inductive loads can also generate electromagnetic interference (EMI), which may affect the operation of nearby equipment.

To improve reliability and extend relay life, always install a contact protection circuit. The circuit should be placed as close to the load as possible (within 12 inches [30 cm]). Installing it farther from the load reduces its effectiveness. Use wire gauges that are appropriately sized for the load current to prevent voltage loss.

Diode selection

• Diode current rating: > 1x strike current

• Diode breakdown voltage: > 4x strike voltage

• For 12 V DC or 24 V DC strike, diode
  1N4002 (100V/1A) typical.

Address and Baud Rate

Switches 1 to 5 select the device address. Switches 6 and 7 select the communication baud rate. All other configuration settings are set via host software.

* DIP switch 8 (S8) is reserved and not used.

Factory Reset

While not normally required, it is possible to perform a factory reset of the single door interface, which deletes all onboard stored data. To perform the delete:

1. Set all DIP switches to OFF.

2. Remove power from the single door interface.

3. Restore power to the single door interface.

4. Within 3 seconds, toggle DIP switch 8 ON.

Status LEDs

Power-up

All LEDs are OFF.

Initialization

Once power is applied, initialization of the module begins. The A LED is turned ON at the beginning of initialization.

Run Time

After a successful initialization, the LEDs have the following meanings:

Specifications

Revision E assembly: The Interface is for use in low voltage, class 2 circuits only.

• Primary power: 12 to 24 V DC ± 10%, 150 mA maximum (reader current not included)

• Outputs: Two Form-C relays: 

  • Normally open contact (NO) contact: 5 A @ 30 V DC resistive

  • Normally closed contact (NC) contact: 3 A @ 30 V DC resistive

• Inputs:

  • Two unsupervised/supervised, standard EOL, 1k/1kΩ, 1%, ¼ watt

  • One unsupervised, dedicated for cabinet tamper

• Reader interface:

  • Reader power: 12 V DC, 600 mA maximum

  • Reader LED output: TTL (Wiegand) compatible, high > 3 V, low < 0.5 V, 5 mA source/sink maximum

  • Buzzer output: Open collector, 12 V DC open circuit maximum, 40 mA sink maximum

  • Data inputs: TTL compatible or 2-wire RS-485

  • Communication: 2-wire RS-485: 38400, 115200 bps

• Cable requirements (all ports shall use shielded conductors):

  • Power: One twisted pair, 18 AWG

  • RS-485 I/O devices: One twisted pair with drain wire and shield, 24 AWG, 120Ω impedance, 4,000 feet (1,200 m) maximum

  • Alarm inputs: One twisted pair per input, 30Ω maximum

  • Outputs: As required for the load

  • Reader data (TTL): 6-conductor, 18 AWG, 500 feet (150 m) maximum

  • Reader data (RS-485): One twisted pair with drain wire and shield, 24 AWG, 120Ω impedance, 2,000 feet (610 m) maximum

• Mechanical:

  • Dimension: 4.25 inches (108 mm) W x 2.75 inches (70 mm) L x 1 inch (25.4 mm) H

  • Weight: 2.9 oz. (83 g) nominal

• Environmental:

  • Temperature:

    • Storage: -55 to +85°C

    • Operating: -40 to +75°C (UL Verified for 0 to 70°C)

  • Humidity: 5 to 95% RHNC

Performance Levels

Evaluated to UL 294 8th edition and ULC 60839-11-1: Grade 2 and indoor dry.

Optional requirements of ULC 60839-11-1 items have not been evaluated.

These specifications are subject to change without notice.

Liability

The Interface should only be used to control exits from areas where an alternative method for exit is available. Thisproduct is not intended for, nor is rated for operation in life-critical control applications. LenelS2 is not liable under any circumstances for loss or damage caused by or partially caused by the misapplication or malfunction of the product. LenelS2’s liability does not extend beyond the purchase price of the product.

Regulatory

This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.

The single door interface board must be powered by an NRTL (Nationally Recognized Testing Laboratory) approved by Class 2 Listed Power Supply. Expansion port and supervised input functionality were not evaluated by UL.

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