Key Features

  • Dual zones, can monitor 2 digital cables
  • Interlock/coincidence detection
  • Displays distances to the alarm point in feet or meters
  • RS-485 communication
  • UL approved


The Digital Interface Monitor Module (DiMM) is a dual zone module for monitoring up to two zones of Digital Linear Heat Detection (DLHD) Cable.

If an overheat or fire situation triggers either zone of the Digital LHD cable, the unit automatically calculates and displays the distance along the cable, in feet and metres, to the alarm point. The two zones can operate independently of each other, or in interlock mode and a separate alarm and normally conducting fault output are provided for each zone.

The unit is intended to be installed between the FyreLine Digital Linear Heat Detection cable and a conventional or addressable fire alarm control panel. It has power, fault and alarm lights, as well as volt free outputs for fault and alarm, corresponding to each zone. It may also be connected to an industrial process control system using the two wire RS-485 Modbus RTU output.


The FyreLine Digital Interface Monitor Module is fully approved by the Underwriters Laboratories (UL) and bears the CE mark to show that they comply with all the applicable Directives including the CPR, EMC and the Low Voltage Directive (LVD).

  • UL 864 10th Edition
    Fire alarm control panels and accessories.

Typical Wiring Diagram

The Digital Interface Monitor Module (DiMM) can be used to provide the location of the point along the cable at which an alarm was triggered, giving an accurate a measurement in metres and feet.

Leader cable can be used between the DiMM and the control panel or addressable switch/zone monitor and between the DiMM and the heat sensing cable. As always a junction box must be used to maintain a secure and waterproof electrical connection.

When using a DiMM it is essential to map the system to associate distances along the detection cable to locations within the building to help determine the area where an alarm has been triggered easily.

Tech Specs

Dimensions (W x H x D)120mm x 180mm x 60.5mm (4.72” x 7.08” x 2.38”)
IP RatingNEMA 4, 4X (IP65)
FinishLight grey with clear lid
Display2 lines, 16 character back-lit display showing zone status
ApprovalsUL 864 10th Edition
Power RequirementsAll circuits power limited if powered from a power limited supply
Operating Voltage12Vdc
Normal Operation (Standby)<12mA
Operating Temperature Range-20ºC to +50ºC (-4ºF to +122ºF)
Supervised CircuitsPower, Input Zone 1 & Input Zone 2
InputsUp to two zones of Fyreline Digital LHD Cable 3000m
Max Zone Length3000m (10,000ft)
Min Zone Length1m (3,2ft)
End of Line Resistor1kohm (included)
Short Circuit Current0.5mA
Max Voltage5V
Ground Fault Impedance0 ohms
CommunicationsTwo wire RS-485 Modbus RTU (field wiring limited to same room to comply with UL listing)
Sounder2.4kHz 92Db @ 10cm Buzzer
Alarm2x Form C volt-free relay contacts (resistive, common)
Max V: 30Vac or 42.4Vdc
Max Current: 2A
Max Switching Power: 60W, 62.5VA
Fault2x Optoisolated photo-transistor output (resistive, common)
Max V: 35Vdc
Max Current: 80mA
Max Power Dissipation: 150mW



Digital Interface Monitor Module, 2 Zone, 1m to 3000m (10,000ft), 12 - 36V DC

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