The doPinpadTransaction method is used in the PinPad flow to continue an ongoing EMV transaction after the initial card capture. This is primarily done to prompt the cardholder to enter a PIN or to exchange additional EMV data (tags) with the payment terminal, advancing the EMV state machine.
Contact Transactions OnlyThis method is relevant to contact transactions (inserted cards), which require a controlled multi-step EMV dialogue involving the terminal and the PIN pad.
Request
JSON-RPC 2.0All methods in TweezerComm follow a JSON-RPC 2.0 structure. See Get Started for more details on how the requests are structured and sent.
- The
method field must be set to doPinpadTransaction.
- The
service must be set to engine in the params.
The request includes the service name and a dictionary of EMV tags that the host system must return to the terminal/card to proceed with the transaction dialogue.
{
"jsonrpc": "2.0",
"method": "doPinpadTransaction",
"id": "123454352",
"params": [
"engine",
{
"tags": {
"95": "tag value",
"9F02": "tag value"
}
}
]
}
Request Parameters
The table below describes the request parameters for this method.
| Name | Type | Description |
|---|
tags | JSON of strings | A dictionary containing the required EMV Tag-Value pairs that the host system must return to the card/terminal to continue the EMV dialogue. |
Response
A successful response indicates that the PinPad transaction state has advanced, either by successfully collecting the PIN from the cardholder or by completing an EMV data exchange round.
{
"jsonrpc": "2.0",
"id": "123454352",
"result": {
"statusCode": 0,
"statusMessage": "ok",
"pem": EMVMANAGER_CONTACT,
"tags": {
"95": "tag value",
"9F02": "tag value",
"5A": "tag value",
"5F34": "tag value",
"5F2A": "tag value",
"9F02": "tag value",
"9F03": "tag value",
"9A": "tag value",
"9C": "tag value",
"9F1A": "tag value",
"9F21": "tag value",
"9F37": "tag value",
"9F36": "tag value",
"9F26": "tag value",
"9F27": "tag value"
}
}
}
Response Parameters
Below is a table with all the possible response parameters and their description:
| Name | Type | Description |
|---|
statusCode | integer | The PinPad transaction status. A value of 0 indicates success. |
statusMessage | string | The transaction message (e.g., ok). |
pem | integer | POS Entry Mode, indicating the method of card entry (e.g., EMVMANAGER_CONTACT). |
tags | JSON of strings | A dictionary containing updated or new EMV Tag-Value pairs from the card/terminal, including information like the masked PAN (5A) or updated cryptograms. |
