Forum Post: TRF7970A as a reader to read RF430CL330H type 4 tag---Question

Hi, 

    I'm working on TRF7970A. TRF7970A as a reader to read/write RF430CL330H type 4 tag, There are some questions:

    I have completed the type B card detection procedure:

    PCD--->

    T: 05 00 04 (REQB)

    R: 50 76 B1 5B 85 00 00 00 11 00 85 A5 (ATQB)

    T: 1D 76 B1 5B 85 00 08 05 08 (ATTRIB)

    R: 88 (ANSWER TO ATTRIB)

NEXT :

 PCD send B2, what's the B2 meaning?

 I have tried 

 T: 00 B2 00 00 01 

or T: B2

 There are no responses.....

 And this command with CRC_B or not?

Thanks.