The D4 connector is one of the older generation connectors which is keyed, and spring loaded and has a 2mm diameter ferrule. Connector body is nickel plated brass for enhanced durability.
 
Features:
  2mm diameter ferrule with spring loaded
  Nickel plated brass connector body
  Precision anti-rotation key
  Low insertion loss and high return loss
 
Applicant：
  Connection of optical transmission equipments E2000-SM-APC
  Telecommunication
  CATV
  LAN (including FITL, FTTH and FTTD)
  ODF of optical transmission systems
  Computer networks
  High speed data transmission networks
 
Compliance:
  IEC-61754-20
  Telcordia-GR-326-CORE
  RoHS
 
Specifications:
Fiber Mode            Unit        SM           MM
Diameter               mm        Ф0.9、Ф2.0、Ф3.0
End-face Finishing              PC  UPC        PC   UPC
Insertion Loss          dB      ≤0.20         ≤0.20 ≤0.40
Return Loss             dB      ≥45 ≥50      ≥45 ≥50
Exchangeability         dB      ≤0.20         ≤0.20