SC APC Cable: The Green Connector With the Angle
Quick answer / TL;DR: Short answer: SC APC is the standard connector for FTTH and CATV because its angled polish gives better return loss, typically below -60 dB. It must not be mated with UPC, which is flat polished and blue. If you need to join the two, use a hybrid adapter as a temporary measure only.
Single-mode patch cords: yellow jacket, LC/UPC, OS2 9/125.SC APC uses a 2.5 mm ferrule polished at an 8 degree angle. The angle sends reflections away from the source, which is why access networks use it.
The green housing is the field indicator, and it is the difference between a working link and a permanent high-loss fault.
Why the Angle
| Polish | Ferrule | Return loss | Colour |
|---|
| UPC | Flat | About -50 dB | Blue |
| APC | 8 degree | Below -60 dB | Green |
Return loss matters in access networks because reflections disturb the laser in a shared PON split.
Practical Rules
- Never mate APC with UPC
- Check colour before connecting
- Clean the end face every time
- Use an angled adapter where types must meet
- Record the polish in the documentation
A UPC plug in an APC socket leaves an air gap at the angle, which can exceed the whole loss budget at the splice.
Real-World Applications
An FTTH drop terminating at an ONT uses SC APC on both ends, matching the splitter port. A data centre patch panel uses UPC, which is why the two estates need separate patch cords and separate labelling.
Standards and Verification
| Reference | Relevance |
|---|
| IEC 61754-4 | SC connector interface |
| IEC 61300-3-35 | End-face inspection |
| ITU-T G.652 | Single mode fibre |
Measured return loss for a specific assembly is not provided in the knowledge base. Require test data per cord.
References
- IEC 61754-4, SC fibre optic connector interfaces
- IEC 61300-3-35, Visual inspection of fibre end faces
- ITU-T G.652, Single-mode fibre
Practical Notes
Keep APC and UPC cords in bags of different colours. The connectors look similar in low light.
Related reading: adapter — blogs/news/adapter
Related reading: sc vs lc connector — blogs/news/sc-vs-lc-connector
Related reading: bulk cable — blogs/news/bulk-cable
Frequently Asked Questions
Can APC mate with UPC?
No. Use a hybrid adapter temporarily at most.
What colour is APC?
Green.
Why use APC?
Better return loss for PON and CATV.
Sourcing cables for a project, a store, or a private-label line? Contact our B2B sales team for specifications, certification evidence, and volume terms – FOB and CIF options available. Request a quote or sample.
