TCK3134 RC and RX_ER assert Conndition

Hi  Team,

We are using TLK3134 with  GMII Mode .

RXC[3:0]  are data valid control singanal and RXC[7:4] are RX_ER control  signal .

Please tell me the factor by which following signals are asserted,

RXC[3:0] 

RXC[7:4] 

Kind regards

Yoshihiro