---
title: "init(instructionClass:instructionCode:p1Parameter:p2Parameter:data:expectedResponseLength:)"
framework: corenfc
role: symbol
role_heading: Initializer
path: "corenfc/nfciso7816apdu/init(instructionclass:instructioncode:p1parameter:p2parameter:data:expectedresponselength:)"
---

# init(instructionClass:instructionCode:p1Parameter:p2Parameter:data:expectedResponseLength:)

Creates an APDU object with the instruction class and code, parameter bytes, and expected response length.

## Declaration

```swift
init(instructionClass: UInt8, instructionCode: UInt8, p1Parameter: UInt8, p2Parameter: UInt8, data: Data, expectedResponseLength: Int)
```

## Parameters

- `instructionClass`: The instruction class (CLA) byte value.
- `instructionCode`: The instruction code (INS) byte value.
- `p1Parameter`: The P1 parameter byte value.
- `p2Parameter`: The P2 parameter byte value.
- `data`: The data to transmit. The APDU object specifies the length of the transmission data in the Lc field.
- `expectedResponseLength`: The expected response data length (Le) in bytes. The value should be one of the following: A length between 1 and 65536 inclusively. –1 when you expect no response data. 256 to send 00 as the short Le field value, assuming the data field is less than 256 bytes. 65536 to send 0000 as the extended Le field.

## Return Value

Return Value A newly initialized ISO 7816 APDU object.

## Discussion

Discussion If your app needs more precise control of the APDU format, use init(data:) to create the APDU object.

## See Also

### Creating an APDU Object

- [init(data:)](corenfc/nfciso7816apdu/init(data:).md)