DS100MB201: have set SEL0 and 1 to 0, but B input can't connect B output, please help to confirm the SCH.

Hi Gary,

You should change R49, R50, R59, and R63 to 0.1uF capacitors.  The DS100MB201 I/O should be AC coupled.

Is there is a common mode voltage associated with the RJ45 component differential outputs?

Regards,

Lee