I try to find out the HW_trigger on the Module. However, there is no " HW trigger" on the board which i can switch logic level. Later on i found out that the Green LED( link LED) shows different status of the connection. When Rj45 connected, voltage is about 0.118V. When unplug RJ45, voltage is about 1.875V. My problem is after i design and wired the circuit as follow. The module is total disable. I can see the Green LED is on, but i can never use tcp/ip to research the module. Could you explain to me why? Thanks
DOC021716.pdf (219 KB)

can not reach/ping module

i think module maybe dead

I had to check the circuit you sent.

Use the LINK LED Pin good idea to control the Tri-state Buffer.

This is expected to work well.

But I did not test,

You check into the test directly.