If you’re just stepping into the world of fiber optics, all the technical terms and abbreviations can feel overwhelming. That’s why I created this fiber glossary series — to help you understand what these terms really mean, in the simplest way possible.

I’ll explain everything from an industry insider’s point of view, using real photos whenever I can (not just fancy renders). I also avoid overly complex explanations, keeping the language clear and direct, so you can be confident you’ll understand the real meaning of these terms after reading.

Today, we’re going to talk about: APC

TABLE OF CONTENTS

So what Is Ethernet PAC ？

APC stands for Angled Physical Contact, and it refers to a type of fiber optic connector with an 8° angled endface.
This angled structure is the key: it redirects any reflected light away from the fiber core instead of sending it straight back.

How to Recognize APC?

  • Color: APC connectors are green.
  • Endface: 8° angled
  • polishTypical Return Loss: Better than –60 dB
  • Common Interface: SC/APC, LC/APC, FC/APC

You can think of APC like a “smart communicator” who slightly turns their head when speaking—this reduces echo (reflection) and keeps the conversation clearer.

Green APC fiber Connector

Where APC Is Commonly Used

APC connectors shine in systems that are extremely sensitive to optical reflections, such as:

  • FTTx and FTTH networks
  • PON systems (OLT–ONU)
  • CATV and RF video services
  • High-precision measurement equipment
  • RFoG networks

In these environments, even a tiny bit of reflected light can cause performance issues, making APC the go-to option.

Learn More About APC&UPC

If you want a deeper comparison between APC and UPC—including test values, performance data, and practical selection tips—check the full guide:
👉 Fiber Optic APC vs UPC – What’s the Real Difference?

Final Thoughts

If you’re still unsure about something, feel free to reach out.

Want to explore more fiber optic terms? Head over to our blog section.

If the term you’re looking for isn’t covered yet, let me know — I’ll add it to the priority list!

And lastly — if you’re a telecom provider, network operator, or involved in fiber infrastructure development and looking for a reliable partner in fiber optic components — feel free to contact us.