Worked Example

This example shows a complete operator checkout flow.

Scenario

  • Terminal IP: 192.168.1.50.
  • ECR port: 10000.
  • Sale amount: EUR 6.50.
  • Application must avoid double charges if the LAN socket drops.

  1. Configure the client.

    const client = createEcr17Client({
  host: "192.168.1.50",
  port: 10000,
  terminalId: "12345678",
  cashRegisterId: "00000001",
  lrcMode: "std",
  autoReconnect: true,
  responseTimeoutMs: 60000,
  ackTimeoutMs: 5000
});

  2. Register events.

    client.setOnConnectionStateChange(setConnectionState);
client.setOnProgress((event) => setPaymentMessage(event.message));
client.setOnReceiptLine((line) => receiptBuffer.push(line.text));

  3. Confirm the terminal is reachable.

    await client.connect();
const status = await client.status();

  4. Collect payment.

    const result = await collectWithRecovery(650);

  5. Persist the structured result.

    savePaymentAttempt({
  amountCents: 650,
  outcome: result.outcome,
  resultCode: result.resultCode,
  stan: result.stan,
  authCode: result.authCode,
  onlineId: result.onlineId
});

Recovery helper

async function collectWithRecovery(amountCents: number) {
  try {
    return await client.pay({ amountCents });
  } catch (error) {
    await client.connect();
    return client.sendLastResult();
  }
}
The helper does not retry pay

It recovers the latest terminal outcome with command G. That is the safety boundary that prevents a duplicate payment command.

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