A bridge tap—also known as star wiring—is a point in your premises where a single cable splits into multiple cables to feed more than one wall socket. This was useful when homes relied on traditional phone lines, because it allowed multiple phones or an ADSL modem to be plugged in around the house.

Before the NBN existed, most homes were connected via Telstra’s copper network. The more phone sockets you had, the more flexibility you had: a phone in the kitchen, another in a bedroom, and your ADSL modem in the study all worked without issue.

However, with the NBN, bridge taps cause more harm than good. NBN signals behave differently to older ADSL signals, and splitting the line can reduce performance or cause instability.

Why Bridge Taps Cause Problems on NBN

Technical explanation:
A bridge tap can create an impedance mismatch on the line, which can cause signal reflections and degrade performance.

Simplified explanation:
Imagine a river splitting into three smaller rivers. The water must divide between them, slowing the flow. If two of those rivers were blocked, the water would move faster and more smoothly through the one remaining channel.
Your NBN line works the same way—one direct cable to one socket provides better speed and stability than a line split into multiple branches.

How to Check If Your NBN Technology Type Can Have a Bridge Tap

Not all NBN technologies use copper, so bridge taps aren’t always possible.

Step 1: Check your NBN technology

1. Go to nbnco.com.au
2. Enter your address
3. Look for “Technology used in your connection”

Technologies not affected by bridge taps:

• HFC
• FTTP
• Fixed Wireless
• Satellite

These do not use copper for the last part of the connection, so bridge taps cannot exist.

Technologies where bridge taps can occur:

• FTTN
• FTTC
• FTTB

These use existing copper cabling in your building, which may still have star wiring present.

How to Test for a Bridge Tap

If a bridge tap is present, more than one wall socket will typically work for an internet connection.

Testing steps:

1. Plug your modem into a wall socket.
2. Leave it connected for 10 minutes.
3. Check whether the internet works.
4. Repeat this test on each socket.

Interpreting the results:

• Only one socket works:
  The bridge tap may have already been removed—but this does not guarantee perfect cabling. A technician test may still be needed.

• More than one socket works:
  You likely have a bridge tap, and this can lead to:

  • slower speeds
  • dropouts
  • reduced stability

If you’re unsure, contact our support team to run tests, or reach out to us to arrange a technician.

How to Remove a Bridge Tap

Only a licensed communications technician can legally modify or remove internal cabling. They can reconfigure your wiring so that there is a single direct cable going to one socket—ideal for NBN performance.

If you’d like help organising a technician, feel free to contact us.