Shenzhen Skyeye CCTV Co. Ltd

IP Cabling Transmission

What are the difference between Mode A and Mode B of Ethernet- Type

In mode A ,Pin 1 and 2 from one side of the 48VDC , And Pin3 and 6 form the other side. These are the same two pairs used for data transmission in  10 BASE-T and 100BASE-TX , allowing the provision of both power and data over onl two pairs in the such networks.

The free polarity allows POE to accommodated for crossover cables,patch cables and auto-MDIX.

In mode B , Pin4 -5 form one side of the DC supply  and pin 7-8 provide the return. These are the 'spare' paris in 10BASE-T and 100BASE-TX. Mode B , therefore , requires 1 4-pair cable.

Mode A and Mode B ::
 Pin Assignment Ethernet-Type
Pins on switch Mode A  Mode B
Ethernet POE (DC)  Ethernet  POE (DC)
Pin1 TX   + TX  
Pin2 TX   + TX  
Pin3 RX    _ RX  
Pin4 NONE   NONE      +
Pin5 NONE   NONE      +
Pin6 RX     _ RX  
Pin7 NONE   NONE      _
Pin8 NONE   NONE       _