User's Manual

PIN Pad 791 Programmer’s Manual (PCI POS-A) UDN PM0103-U Rev. 06
Section 6 – Contact EMV Level 2 transaction messages 2015-04-20
Page112
Uniform Industrial Corp. Proprietary and Confidential Total 342 pages
Message T29 Get Reversal Data
Format: <STX>T29<ETX>[LRC]
Message length: Fixed 6 bytes.
Usage: Issue this message to get data (EMV) for reversal.
Message element:
Field Length Value and description
<STX> 1 <02>
T29 3 Message ID
<ETX> 1 <03>
[LRC] 1 Checksum
While the EMV transaction needs a reversal, issuing message T29 to get the necessary data for reversal
from PIN pad. User can load a tag list for reversal data into PIN pad, PIN pad will search the
corresponding values according to the tag list and return it as transaction record. Please refer to
Appendix D for more details.
Message flow:
HOST Direction PIN pad
Message T29


<ACK> (Good LRC)
<NAK> (Bad LRC)
<EOT> (after 3 NAKs)

Message T2A
<ACK> (Good LRC)
<NAK> (Bad LRC)
<EOT> (after 3 NAKs)

Note. Terminal could always get reversal data even if the message T16 indicates that the reversal is not
needed.