====== Fibers ======

===== Multimode MM =====

Core diameter 50 or 62,5 micron.
Lower cost of LED sources and lasers operation at 850nm and 1300nm.
  * OM1 62.5/125um (up to 622Mbit / 10Gbit @33 meters) - obsolete
  * OM2 50/125 um (up to 622Mbit / 10Gbit @82 meters) - popular
  * OM3 50/125 um (850nm laser optimized up to 10Gbit/s / 10 Gbit @300 meters)
  * OM4 50/125 um (850nm laser optimized up to 100Gbit/s / 10 Gbit @550 meters)

===== Single Mode SM ===== 

Wavelength 1310 or 1550 nm.

  * OS1 ITU-T G.652A or ITU-T G.652B
    * Indoor (tight-buffered construction)
    * max att 1.0 db/km
    * max distance 1km
    * cheaper

  * OS2 
    * Outdoor (loose-tube design)
    * are only compliant with ITU-T G.652C or ITU-T G.652D standards.
    * which  means OS2 is explicitly applied to the low-water-peak fibers. These low-water-peak fibers are usually used for CWDM (Coarse Wavelength Division Multiplexing) applications.
    * appropriate for outdoor cases like street, underground and burial
    * max att 0.4db/km.
    * max distance 10 km

  * G.652D
    * full spectrum fibers (no high loss in 1360 – 1460 nm)
    * suitable for WDM

====== Transmit Window ======
  * 850 nm - I (MM)
  * 1300 nm - II (MM)
  * 1310 nm - II (SM)
  * 1550 nm - III (SM)
  * 1625 nm - IV

====== cable color =====

  * Yellow - single mode
  * White - for end user home installation - single mode
  * Orange - multimode OM1/OM2
  * Turquoise - multimode OM3
  * Turquoise / Violet - multimode OM4

====== Connector ======

Square Connectors:
  * ST - obsolete - looks like RF BNC connector. Push and rotate to lock.
  * SC - bigger (more popular, older)
  * LC - smaller, half size of SC (Lucent, less popular, license fees)
    * popular for SFP adapters as full fuplex pairs with plastic lock mechanism
  * E2000


Fiber polishing:
  * APC (Angled Physical Contact) - face of fiber is filed by 8 or 9 degree. Less attentuation. (-70dB)
    * Marking (plug) color: GREEN.
  * UPC/PC (Ultra Physical Contact) - polished diagonally (-40dB). 
    * Marking (plug) color BLUE or BEIGE.

===== Pigtails =====

End user:
  * green rectangle plugs - FO SM SC/APC-SC/APC SIMPLEX

End user (Orange):
  * green rectangle plugs and yellow cable - single mode, APC polishing