This part is a kind of semiconductor called HN16012CG.

Function of this product has 10/100 Base-T Single Port Transformer.

Manufacturers : Mingtek

Image and pinout :

Some of the text within the PDF file :

www.DataSheet.co.kr Mingtek Features Electrical Specifications @25¢J 10/100 Base-T Single Port Transformer For Modules  IEEE 802.3 Ethernet Compatible,10/100 Base-TX  Surface Mountable(Miniature size)  Product Type: Green Product Rise Time & Fall Time @5.0ns(Max), Isolation Hi-pot:1500Vrms(pri/sec), Pri.OCL:Tx&Rx:350µH min @Idc=8mA Insertion Loss Return Loss Cross Talk DCMR CWW Pri. Resistance Turn Ratio Tx/Rx (dB Max) (dB Min) (dB Min) (dB Min) (pF typ) (Ω Max) (±5%) Part No. 1-100 0.5-30 40 60 80 0.1-100 0.1-100 Tx&Rx 0.1 MHz MHz MHz MHz MHz HN16012CG -1.1 -18 -15 -13 -11 -35 -30 15 0.9 1CT:1CT / 1CT:1CT HN16015CG -1.0 -18 -17 -14.5 -12 -35 -30 15 0.9 1CT:1CT / 1CT:1CT HN16016CG -1.1 -18 -16 -13 -12 -35 -30 15 0.9 1CT:1CT / 1CT:1CT HN16017CG -1.0 -18 -17 -14.5 -12 -32 -3 [ ... ]

HN16012CG PDF Datasheet Download