A simple, scalable, and cost‑effective entry communication solution for multi‑unit residential buildings, small offices, and shared entrances.

For buildings with multiple units – duplexes, triplexes, small apartment buildings, or shared office spaces – a single call button is rarely enough. Visitors need a way to reach the right resident or office, and residents need a way to communicate with visitors and control entry.

That is where a 3‑button audio intercom system comes in. With three call buttons on the outdoor station و dedicated indoor handsets for each unit, this system provides clear, reliable audio communication between visitors and residents – without the complexity or cost of video, Wi‑Fi, or smartphone apps.

This guide covers everything you need to know about connecting and using a 3‑button audio intercom system – from wiring and installation to configuration and troubleshooting.

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Why Choose a 3‑Button Audio Intercom?

Audio intercoms remain one of the most cost‑effective and reliable entry communication solutions available. Here is why they are still a popular choice for multi‑unit buildings:

• Supports multiple units – Three call buttons allow up to three residents or offices to be reached from a single outdoor station.
• تركيب بسيط – Most systems use straightforward wiring between the outdoor station and each indoor handset.
• لا توجد تبعية للإنترنت – Works without Wi‑Fi, cloud services, or smartphone apps. Reliable communication, always.
• Low cost – Significantly cheaper than video or IP systems – both in hardware and installation.
• Low maintenance – Fewer components mean fewer things that can fail. No firmware updates, no battery changes.
• Easy to use – Visitors press the button for the desired unit. Residents pick up the handset and talk. Everyone understands it instantly.
• Expandable – Up to four indoor units can be connected per residential unit, with serial or parallel wiring options.

الأفضل لـ: Duplexes, triplexes, small apartment buildings (up to 3 units), shared office entrances, and budget‑conscious residential projects.

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What’s in the System?

A 3‑button audio intercom system consists of the following components:

مكون	الوصف
محطة خارجية	Mounted at the entrance. Features three call buttons (one per unit/office), microphone, and speaker. Weatherproof (IP65) for outdoor installation.
Indoor Handsets	One handset for each unit or office. Features a handset (or hands‑free speaker), talk button, and unlock button.
مصدر الطاقة	Provides low‑voltage power to the system. Typically a plug‑in adapter (e.g., 12V or 24V DC).
Electric Lock (optional)	Connected to the indoor handsets or outdoor station for remote door unlocking.

Typical scope of delivery for a 3‑button system:

• 1x Outdoor station with three call buttons
• 3x Indoor handsets (one for each unit)
• 1x Power supply
• Assembly materials and mounting hardware

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Step‑by‑Step Connection Guide

⚠️ Important: Before starting any wiring, disconnect power to avoid damaging the system. Always follow the specific wiring diagram provided with your kit. Incorrect wiring can damage the system.

Step 1: Plan Your Installation

• Outdoor station – Mount near the entrance at approximately 1.4 to 1.5 metres (eye level). Choose a location sheltered from direct rain where possible.
• Indoor handsets – Mount one handset in each unit or office at a convenient location – hallway, living room, or reception area – where residents can easily hear the ringtone and answer calls.
• Plan the cable routes between the outdoor station and each indoor handset. For a 3‑button system, 3 lines are required per call button from the outdoor unit to each residential unit.

Step 2: Choose Your Cable

Most 3‑button audio intercom systems use multi‑conductor wiring between the outdoor station and indoor handsets. Suitable cable types include:

• Twisted pair cable (e.g., Cat5 or telecoms wire)
• Doorbell wire (multi‑core)
• Standard multi‑core cable (≥0.5mm²)

نصيحة: For longer distances (over 50 metres), use heavier gauge cable (e.g., 0.75mm² or 1.0mm²) to reduce voltage drop.

Step 3: Wiring Options

There are two main wiring configurations for connecting multiple indoor handsets to a single outdoor station:

1. Serial Connection (Daisy‑Chain)

• Indoor handsets are connected in series – from one handset to the next.
• Simplifies cabling but may require careful addressing of each unit.

2. Radial Connection (Parallel)

• Each indoor handset is wired independently from a central distribution point.
• More wiring but offers easier troubleshooting and independent operation.

ملاحظة: الـ radial wiring system is generally preferable for its reliability and ease of maintenance.

Step 4: Connect the Outdoor Station

1. Mount the outdoor station securely to the wall or gatepost using the included bracket.
2. Connect the cables from each indoor handset to the corresponding terminals on the outdoor station.
3. Terminals typically include:
   • Communication terminals – for audio and call signals to each indoor handset
   • Lock terminals – for connecting to an electric lock (typically NO و COM for relay output)
   • Power terminals – for connecting to the power supply

Step 5: Connect the Indoor Handsets

1. Mount each indoor handset on the wall using the included bracket.
2. Connect the cables from each handset to the outdoor station (or to the central distribution point for radial wiring).
3. For serial wiring, connect from one handset to the next in sequence.
4. If connecting an electric lock, connect the lock wires to the unlock relay terminals on one of the handsets (or the outdoor station).

Step 6: Connect the Power Supply

1. Connect the power supply to the system (typically via the outdoor station or a central distribution point).
2. Plug the power adapter into a wall outlet.
3. Check the LED indicators on the outdoor station and indoor handsets – they should light up, indicating power is supplied.

Step 7: Configure and Test the System

1. Test each button – Press call button 1, 2, and 3 on the outdoor station. The corresponding indoor handset should ring.
2. Test audio – Pick up each handset (or press the talk button) – you should hear clear two‑way audio with the visitor.
3. Test unlock – Press the unlock button on each handset – the door lock (if connected) should release.
4. Adjust volume – Most handsets have volume controls for both ringtone and speech.
5. Set ringtones – Some systems allow different ringtones to differentiate call sources (e.g., main door vs. side entrance).

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Terminal connections (typical system):

Terminal	محطة خارجية	Indoor Handset
1	Call button 1 / Communication	الاتصال
2	Call button 2 / Communication	الاتصال
3	Call button 3 / Communication	الاتصال
Lock (optional)	NO / COM	NO / COM (on one handset)
الطاقة	DC input	Powered via outdoor station

ملاحظة: For a single‑family house, 3 lines are required from the outdoor unit to the indoor unit و 2 lines from the outdoor unit to the door opener.

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Key Features & Functions

📞 Three Dedicated Call Buttons

Each button on the outdoor station corresponds to a specific unit or office. Visitors simply press the button for the resident they want to reach – no directory, no codes, no confusion.

🗣️ Two‑Way Audio

Full‑duplex audio allows natural conversation between visitor and resident. The outdoor station’s weatherproof speaker and microphone ensure clear communication even in noisy or windy conditions.

🔓 Remote Unlock

Residents can unlock the door by pressing the unlock button on their indoor handset. Compatible with most electric locks – electric control locks, magnetic locks, and electric strikes.

🔔 Multiple Ringtones

Some systems support up to five different ringtones to differentiate between various call sources – for example, distinguishing a call from the main entrance from a call from a secondary entrance or a guard unit.

📊 System Status LEDs

LED indicators on the indoor handset provide system status information – power, call active, door lock status, and more.

🎚️ Adjustable Volume

Side switches or buttons allow adjustment of ringtone volume and speech volume.

🏗️ Expandable

Up to four indoor units can be connected in parallel per residential unit. Multiple outdoor stations can also be supported in larger systems.

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Common Features of the Indoor Handset

A typical 3‑button audio intercom indoor handset includes:

ميزة	الوصف
Unlock Button	Releases the connected door lock
Auxiliary Buttons	Programmable for additional functions – calling the outdoor station, releasing a second lock, checking lock status
Handset	Provides clear audio communication
التحكم في مستوى الصوت	Adjustable via side switch (max‑mid‑mute)
Ringtones	Up to 5 different ringtones to differentiate call sources
LED Indicators	System status indications

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استكشاف مشكلات شائعة وإصلاحها

المشكلة	Possible Solution
No power / no LED	Check the power adapter connection. Ensure the outlet is working. Check the fuse (if applicable).
One or more buttons not ringing	Verify the wiring from the outdoor station to the corresponding indoor handset. Check for loose connections or broken wires.
No audio or poor audio	Check cable quality and connections. For long distances, use thicker gauge cable. Adjust volume settings on the handset.
Door lock not releasing	Check lock wiring connections. Ensure the lock power supply is adequate. Verify the unlock relay is working (listen for a click).
Intermittent issues	Check for loose connections, corrosion on terminals, or damaged cables.
Wrong handset ringing	Check the wiring configuration – ensure each call button is connected to the correct indoor handset.

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Why Choose FARHD Audio Intercoms?

FARHD is a professional OEM/ODM manufacturer with over 28 years of experience in video and audio intercom R&D and manufacturing. Since 1998, we have been delivering high‑quality intercom systems and one‑stop solutions to clients worldwide.

• Founded in 1998 – 28+ years of intercom expertise
• Source factory – Competitive pricing, full quality control
• OEM / ODM supported – Custom logo, packaging, and configurations available
• وصول عالمي – Serving clients in over 90 countries
• No MOQ for trial orders – Start with a sample; scale as you grow
• Complete product range – Audio, 2‑wire, 4‑wire, IP, SIP, and wireless intercom systems

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Ready to Install Your 3‑Button Audio Intercom?

الـ 3‑button audio intercom system is the simplest, most reliable way to add entry communication to duplexes, triplexes, small apartment buildings, and shared office entrances. With three dedicated call buttons, dedicated indoor handsets for each unit, and straightforward wiring, you can have clear, reliable communication between your entrance and indoor spaces – no internet, no apps, no complexity.

📩 Contact us for catalog, pricing, or to request a sample.

🌐 Website: www.farhd.com
📧 Email: [email protected]

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FARHD – Video & Audio Intercom Manufacturer Since 1998.