The rollout of the National Broadband Network (NBN) has transformed internet connectivity in Australia, providing faster and more reliable internet services. However, many homeowners and businesses are still unclear about the compatibility of NBN telephone cable with different NBN technologies. Understanding how these cables work and their compatibility with various NBN connection types is essential for ensuring a seamless internet and phone service.
In this article, we’ll explore the role of NBN telephone cables, their compatibility with different NBN technologies, and how to ensure proper installation for optimal performance. If you’re looking for expert NBN cabling services, Value Services offers professional support to help you set up and maintain your NBN connection.

Table of Contents
What Is an NBN Telephone Cable?
An NBN telephone cable is a physical cable that connects your telephone or other communication devices to the NBN (National Broadband Network). It plays a crucial role in transmitting voice signals over the NBN infrastructure, ensuring clear and reliable phone service.
How It Works:
- Connection to NBN Wall Socket or NTD
The NBN telephone cable typically plugs into an NBN wall socket or directly into the NBN connection box (NTD). This allows your telephone or modem to communicate with the NBN network. - Transmission of Voice Signals
The cable carries voice signals in the form of electrical or digital data between your devices and the NBN network. This enables voice calls to be made and received using the NBN infrastructure. - Compatibility with VoIP (Voice over Internet Protocol)
Since the NBN primarily operates using VoIP technology, the NBN telephone cable is essential for converting traditional voice signals into digital signals that can be transmitted over the internet.
Types of NBN Telephone Cable
There are several types of cables used to connect telephone and communication devices to the NBN network. Each type serves a specific purpose depending on the type of connection and the equipment being used.
1. RJ11 Cable
- Purpose: Primarily used for connecting telephone handsets and phones to modems or wall sockets.
- Compatibility: Suitable for traditional phone services over NBN, especially for VoIP (Voice over Internet Protocol) setups.
- Design:
- Smaller connector with 4 or 6 pins.
- Often used in FTTN (Fibre to the Node) and FTTC (Fibre to the Curb) connections.
Example: If you have an NBN connection with a phone service through VoIP, you’ll likely use an RJ11 cable to plug the phone into the modem or NTD.
2. RJ45 Cable
- Purpose: Used for both internet and data transmission; sometimes adapted for telephone use in more complex setups.
- Compatibility: Commonly used for high-speed internet connections but can also support voice transmission in some configurations.
- Design:
- Larger than RJ11 with 8 pins.
- Often used for direct connections to modems and routers for better data speeds.
Example: If your phone system is integrated with a data network, you might use an RJ45 cable to handle both voice and data transmission.
3. Cat5e and Cat6 Cables
- Purpose: High-speed data cables that are also capable of transmitting voice signals.
- Compatibility: Commonly used for structured cabling in homes and offices to support both internet and phone lines.
- Design:
- Cat5e: Supports up to 1 Gbps speeds.
- Cat6: Supports up to 10 Gbps speeds over short distances.
- Uses RJ45 connectors for versatile data and voice connections.
Example: If you have a home office setup with both internet and phone lines, you might use Cat6 cables to ensure fast and stable transmission.
4. DSL Cable
- Purpose: Used for connecting older phone systems or ADSL/VDSL modems to NBN-compatible setups.
- Compatibility: Often used with FTTN and FTTC connections where a phone line is required for the internet connection.
- Design:
- Similar to an RJ11 cable but specifically designed for DSL signals.
- Can transmit both data and voice signals over a single line.
Example: If you are transitioning from a traditional copper phone line to an NBN service, you may use a DSL cable during the switchover.
✅ Summary
Cable Type | Primary Use | Connector Type | Max Speed | Compatibility |
---|---|---|---|---|
RJ11 | Telephone handsets, modems | 4 or 6-pin | Low | VoIP, FTTN, FTTC |
RJ45 | Internet and voice | 8-pin | High | Modems, routers, integrated systems |
Cat5e/Cat6 | High-speed data and voice | 8-pin (RJ45) | 1 Gbps (Cat5e), 10 Gbps (Cat6) | Data networks, phones |
DSL | Older phone systems | Similar to RJ11 | Low to Medium | FTTN, FTTC, ADSL/VDSL |
Compatibility of NBN Telephone Cables with Different NBN Technologies
The compatibility of NBN telephone cable depends largely on the type of NBN connection used at your premises. Below is a detailed table outlining compatibility across different NBN technologies:
NBN Technology Type | Compatible Telephone Cable | Additional Notes |
---|---|---|
Fibre to the Premises (FTTP) | RJ11, RJ45, Cat5e, Cat6 | RJ11 for voice, RJ45 for data |
Fibre to the Node (FTTN) | RJ11, Cat5e, Cat6 | RJ11 for VDSL modem connection |
Fibre to the Curb (FTTC) | RJ11, Cat5e, Cat6 | Requires a DSL connection |
Hybrid Fibre Coaxial (HFC) | RJ11, Cat5e, Cat6 | RJ11 for telephone connection to the NTD |
Fixed Wireless | RJ11, RJ45, Cat5e, Cat6 | RJ11 for phone, RJ45 for data |
Satellite (Sky Muster) | RJ11, RJ45, Cat5e, Cat6 | RJ11 for phone, RJ45 for router |

How to Connect an NBN Telephone Cable
Setting up an NBN telephone cable properly is essential for a stable and reliable connection for both phone and internet services. Below are step-by-step instructions to help you connect your NBN telephone cable correctly:
1. Identify the Connection Type
The first step is to determine which type of NBN connection you have. The type of NBN connection will affect how your telephone cable is set up. The main NBN connection types are:
- FTTP (Fibre to the Premises): Direct fibre optic cable to your home; phone connects to the NBN connection box (NTD).
- FTTN (Fibre to the Node): Uses existing copper lines; phone connects via the modem/router.
- FTTC (Fibre to the Curb): Fibre optic cable to the street, then copper to the home; phone connects via the modem.
- HFC (Hybrid Fibre Coaxial): Uses a coaxial cable; phone connects via the modem.
- Fixed Wireless: Uses a wireless signal to an antenna; phone connects via the modem.
- Satellite: Uses a satellite dish; phone connects via the modem.
✅ Why It Matters:
- For FTTP, the phone connects to the NBN connection box (NTD).
- For FTTN and FTTC, the phone connects to the modem.
- For HFC, Fixed Wireless, and Satellite, the phone connects to the modem or router.
2. Locate the NBN Wall Socket or NTD
Find the physical point where the NBN network enters your home:
- For FTTP, HFC, and Fixed Wireless – You’ll have an NBN connection box (NTD) installed inside your home.
- For FTTN and FTTC – You’ll have an NBN wall socket (which looks like a phone socket).
- For Satellite – The connection point is usually near the satellite receiver’s indoor unit
3. Use the Correct Cable
Select the right cable for your setup:
- RJ11 Cable – Used for connecting telephone handsets directly to the modem or wall socket.
- RJ45 Cable – Used for high-speed internet or when setting up integrated phone and data systems.
- Cat5e/Cat6 Cable – Used for connecting phones or data points to routers and modems.
- DSL Cable – Used for FTTN and FTTC setups that rely on copper phone lines.
4. Connect to the Modem/Router
Once you’ve identified the correct cable and connection type:
- For FTTP – Plug the RJ11 or RJ45 cable directly into the phone port on the NBN connection box (NTD).
- For FTTN/FTTC – Plug the RJ11 cable into the phone port on the modem.
- For HFC, Fixed Wireless, and Satellite – Plug the RJ11 cable into the phone port on the modem/router.
- For integrated data and phone networks, use RJ45 or Cat5e/Cat6 cables.
5. Test the Connection
After connecting the cables:
- Pick up the phone and check for a dial tone (if using a phone service).
- Test the internet connection by opening a website or running a speed test.
- If there’s no dial tone or connection, try:
- Restarting the modem/router.
- Checking if the correct port is being used.
- Ensuring the cables are firmly connected.
✅ Summary
Step | Action | Notes |
---|---|---|
1. Identify Connection Type | Determine FTTP, FTTN, FTTC, HFC, Fixed Wireless, or Satellite | Affects setup method |
2. Locate Wall Socket/NTD | Find the NBN connection point | NTD or wall socket location matters |
3. Use Correct Cable | RJ11, RJ45, Cat5e/Cat6, or DSL cable | Based on connection type |
4. Connect to Modem/Router | Plug cable into correct port | Use phone or data port |
5. Test the Connection | Check for dial tone or internet | Restart if needed |
Frequently Asked Questions (FAQs)
1. Can I use a standard telephone cable for NBN?
Yes, standard RJ11 telephone cables are compatible with most NBN technologies for voice services. However, for internet and data transmission, you may need an RJ45 or Cat5e/Cat6 cable.
2. Do I need a special cable for FTTP connections?
No, FTTP connections typically use standard RJ11 and RJ45 cables for telephone and internet services.
3. Why is my NBN telephone not working after installation?
Ensure the telephone is plugged into the correct port on the NBN connection box. Also, check for compatibility issues or damaged cables.

Conclusion
NBN telephone cables are essential for maintaining reliable voice and internet services over the National Broadband Network. While RJ11 cables are typically used for telephone connections, RJ45 and Cat5e/Cat6 cables are often required for data transmission. Compatibility with different NBN technologies depends on the type of connection at your property.
For professional installation, troubleshooting, or upgrades, contact Value Services. Their experienced technicians will ensure your NBN telephone cables are correctly installed and functioning at their best.