User's Manual

PIN Pad 791 Programmer’s Manual (PCI POS-A) UDN PM0103-U Rev. 06
Section 9 – Online transaction messages with Master / Session keys 2015-04-20
Page221
Uniform Industrial Corp. Proprietary and Confidential Total 342 pages
Message Z42 Read Key Code
Format: <STX>Z42[timeout]<ETX>[LRC]
Message length: Variable 6 to 9 bytes.
Usage: Once PP791 receives this command, it begins polling functional key array until timeout.
If PP791 received Z2 / Z3 authenticated frame before Z42, it will return any key
pressed by user by ASCII key codes via message Z43. Else it will return only function
key codes (F1, F2, F3, CAN, CLR, ENTER), and reject numerical key (0 to 9). Multiple
key press or combined key press will be discarded.
Abort input: Issue message 72 to abort the operation.
Note: Z2/Z3 required: Because Z42 will not show any message to prompt user operation, Z2
or Z3 should be issued before this command, or PIN pad will send <EOT> and stop.
Message element:
Field Length Value and description
<STX> 1 <02>
Z42 3 Message ID
[timeout] 1 to 3 ASCII character from 1 to 255, for
example “10” means 10 seconds timeout.
<ETX> 1 <03>
[LRC] 1 Checksum
Message flow:
HOST Direction PP791
Message Z2 or Z3


<ACK> (Good LRC)
<NAK> (Bad LRC)
<EOT> (after 3 NAKs)
Show prompt message
Message Z42


<ACK> (Good LRC)
<NAK> (Bad LRC)
<EOT> (after 3 NAKs)

Message Z43
<ACK>/<NAK>/<EOT>
