title: Difference between 'Direct Transmit Command' (ACR122U) and 'PC_to_RDR_Escape' (ACR1251U)
body: <p>With an ACR122U I know you can transmit direct messages to the NFC controller (PN532) by using the direct transmit command: <code>0xff 0x00 0x00 0x00...</code>. </p>
  
  <p>When I read the manual of the ACR1251U it say: <em>The reader's peripherals control commands are implemented by using the PC_to_RDR_Escape</em>. </p>
  
  <p>What does this exacly mean? Does this mean it isn't possible to send direct messages to the NFC controller? If it is possible, where can you find which NFC controller it use?</p>
  
  <p>Any information is welcome!</p>
  
  <p>Thanks in advance.</p>