Difference between SC/APC and SC/UPC

SC/APC

  • Full name: Angle-Polished Connectors 
  • Green in body
  • End Face is polished at 8 degree angle and causes the reflected light to be absorbed by the cladding instead of source
  • Return Loss = -65 db
  • Superior feature makes it the favorite connector in today FTTH (Fibre-To-The-Home) system
  • Deployed in OpenNet FTTH system 
  • Used by all telco fibre plan services to connect to ONT
  • Higher cost due to its distinctive function  
  • offered in DE Online Shop & Dealer Shop

SC/UPC or SC/PC

  • Full name: Ultra-Polished Connectors
  • Blue in body
  • End Face is polished at 0 degree angle, light will be reflected back to source
  • Return Loss = -55db
  • Reflected signal to the source tends to degrade or attenuate the downstream signal, and there is a cross-modulating effect in the analog signals. When converting back to an analog RF signal. There is a ghosting or shadowing effect in the viewed signal at the television set.

Why OpenNet TP can only be connected with SC/APC patchcords




All connectors under OpenNet Infrastructure are APC type.  

As shown in the picture, inside every home's Fibre Termination Box, it is green SC/APC type connector fitting into the green adapter.

The green colour adapter is to indicate the type of patchcords that can be fitted into it since both SC/APC and SC/UPC are identical other than the polished head.    

When adapter is inserted with APC type patchcords, it is a perfect match. Reflected light will be absorbed by the cladding instead of returning back to source.

When the TP is mated with UPC type patchcords, it could damage the ceramic material that surrounds the fibre. The air gap in between will cause high signal losses. 

Only same type of patchcords are allowed to be mated with each other. The concept is further illustrated at the right-hand side picture showing UPC-UPC type mating. 
Reference: