The elevator five-way intercom system is a mandatory safety communication system required in modern elevators. Although it is often considered a low-complexity, low-voltage system, its reliability is critical during elevator inspections and emergency rescue situations.
This article provides a complete guide to the elevator five-way intercom system, covering system definition, functions, wiring standards, testing requirements, and a practical FAQ-style troubleshooting section for technicians and elevator companies.
What Is an Elevator Five-Way Intercom System?
An elevator five-way intercom system allows voice communication between five key locations:
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Monitoring Center / Duty Room (Main Unit)
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Elevator Car
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Machine Room
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Car Roof
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Elevator Pit
Among these, communication between the elevator car and the monitoring center is the most critical, as it directly ensures passenger safety during emergencies.
Why Is the Elevator Five-Way Intercom System Important?
The primary purpose of the elevator five-way intercom system is emergency communication. When passengers are trapped due to elevator failure, the system enables immediate contact with rescue personnel—especially when mobile phones are unavailable or signal coverage is poor.
For this reason, the five-way intercom system is a key inspection item during elevator acceptance and a legally required safety configuration in many regions.
Main Functions of the Five-Way Intercom System
The elevator five-way intercom system belongs to the security intercom category and is designed specifically for elevator environments. Its core functions include:
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Multi-point communication between the monitoring center, machine room, elevator car, car roof, and pit
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One-to-one communication via switching equipment after a call is initiated from the elevator car
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Full engineering interfaces for system integration
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Centralized calling from the control center to multiple elevators simultaneously
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Fault signal transmission to the monitoring center, with precise elevator identification confirmed through one-to-one communication
System Responsibility and Wiring Standards
Responsibility Division
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Intercom host units for the machine room and monitoring center are usually provided by the elevator manufacturer
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Cabling between the machine room and monitoring center is typically completed by the low-voltage or intelligent systems contractor
Recommended Wiring Specifications
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Cable type: PVC-sheathed shielded flexible cable
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Model: RVVP 2×1.0 mm²
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Cable reservation:
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≥ 2 meters at the monitoring center intercom host
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≥ 2 meters at the elevator control cabinet
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Maximum wiring distance: ≤ 2 km
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Average internal resistance: ≤ 4Ω per 100 meters
Line Testing and Acceptance Requirements
To ensure stable communication quality, the intercom wiring must meet the following testing standards:
Insulation Resistance Test
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Test voltage: 500V
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Resistance between ground wire and signal wires, and between signal wires: ≥ 0.02 MΩ
Multimeter Testing
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AC Voltage: Induced voltage between signal wires and ground ≤ 48V (system powered on)
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DC Voltage: Voltage between signal wires and ground, and between signal wires themselves should be 0V
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Resistance Test: With the communication trunk short-circuited in the machine room, resistance measured at the monitoring center should be ≤ 120Ω
Elevator Five-Way Intercom FAQ: Common Faults and Solutions
Q1: Why does the substation fail to call the main unit?
Possible causes and solutions:
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If multiple substations cannot call: check ID codes and main channel settings on the main unit
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If only one substation fails: re-pair the ID code
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Replace the faulty unit with a known working one for testing
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If replacement works, the original substation is defective and should be returned for repair
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If not, check power supply and antenna connections
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If all settings are correct, the main unit may be faulty
Q2: Why does the call disconnect or contain noise?
Troubleshooting steps:
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Check whether the antenna is securely connected and properly positioned
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Ensure the antenna is placed in an open, unobstructed area
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Verify UPS power supply voltage (12–14V)
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Replace power supply units if necessary
Q3: Why can the main unit hear the elevator car, but the car cannot hear the main unit?
Possible reasons:
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Loose or faulty handset connection
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Test with a known good handset from the machine room
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If multiple substations show the same issue, the main unit may need factory repair
Q4: Why cannot the substation call out at all?
Checklist:
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Check whether the signal wires are connected incorrectly or reversed
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Most car stations have indicator lights—correct wiring will activate the light
Q5: Why is there howling or feedback during communication?
Common causes:
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The car station is not tightly mounted to the panel, leaving gaps
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The car station itself may be defective and require replacement
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In three-way systems, confirm that car roof and pit stations have been removed
Q6: Why is the volume in the elevator car extremely low?
Recommended checks:
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Confirm whether signal wires pass through the elevator control board; reroute externally if needed
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Replace the car station if volume remains insufficient
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Ensure the microphone aligns correctly with the panel sound hole
Conclusion
The elevator five-way intercom system is a mandatory safety communication device designed to protect passengers and improve emergency response efficiency. While the system itself is not technically complex, standardized wiring, qualified cable quality, and clear responsibility division are essential to ensure reliable operation.
Proper installation and testing of the elevator five-way intercom system are not optional—they are fundamental to elevator safety compliance.
