Communication Conventions and General Specifications

Category: Interface — Embedded Direct-Connect (TCP)

Read the communication conventions first — verify the request address, command, and success/failure return values.

What to prepare before starting?

First confirm the internal unit model, firmware, and device IP; the current communication spec uses a local HTTP address and CMD_ID commands.

The category name contains "TCP", but the actual request method follows "Communication Conventions and General Specifications". The call examples here apply only to the embedded protocol.

Next: Query Internal Unit →

Document version: 1.0 (2026-06-13) Encoding: UTF-8 · JSON

1. Interface Overview

This protocol is the "TCP Ruifengcai LAN Protocol". All queries, printing, and progress polling are completed through the unified entry point POST /api/app_print.

• The printer starts its HTTP service about 10 seconds after connection, on default port 8555.
• Unified entry POST /api/app_print, JSON request / JSON response.
• Supported commands: CMD_ID = 00 01 02 03 04.

2. Communication Conventions

Note: {deviceIP} must be replaced with the actual printer IP; do not hardcode a single machine's address. The default port is 8555.

3. General Request Body

{ "CMD_ID": "00" }

All requests must include CMD_ID; other fields are described per command.

4. General Response Format

4.1 Success Response

{ "CMD_ID": "00", "code": 0 }

Fixed fields: CMD_ID, code (0 = success). Each command's additional business fields are described below.

4.2 Failure Response

Fixed fields: code (-1 = failure), msg (failure reason). When CMD_ID can be parsed, it is echoed back as-is.

Business failure (HTTP 200)

{ "CMD_ID": "00", "code": -1, "msg": "failure reason" }

Request unparseable (HTTP 400, possibly no CMD_ID)

{ "code": -1, "msg": "CMD_ID cannot be empty" }

Note: Business success or failure is determined by the JSON code, not by the HTTP status code alone.

5. Command Overview

If the device encounters an unsolvable problem during debugging, contact the cloud-printing owner to troubleshoot and find a solution. Contact details are as follows:

• Phone: 137-5177-4454 (WeChat same number)
• Email: info@ColorPark.cn