---
title: "Modbus RTU vs Modbus TCP - which to use?"
canonical: "https://www.kies.com.cn/en/kb/modbus-rtu-vs-tcp"
lang: "en"
type: "knowledge-base"
publisher: "Shanghai Paixu Network Technology Co., Ltd."
pricing: "mixed"
kb_type: "qa"
alternate: "https://www.kies.com.cn/zh/kb/modbus-rtu-vs-tcp.md"
---

# Modbus RTU vs Modbus TCP - which to use?

> Source (canonical): https://www.kies.com.cn/en/kb/modbus-rtu-vs-tcp
> Published by: Shanghai Paixu Network Technology Co., Ltd. — B2B supplier of AI devices and robotics
> Type: Q&A
> Language: English · Also available in Chinese: https://www.kies.com.cn/zh/kb/modbus-rtu-vs-tcp.md

## Answer

RTU runs on RS-485 serial - simple wiring, cheap devices, fine for local small-scale acquisition. TCP runs on Ethernet - faster, routable, IT-friendly. Retrofits typically use a gateway to bridge legacy RTU devices to TCP/MQTT.

## Details

Modbus RTU is a serial protocol on RS-485 - one twisted pair daisy-chains dozens of meters at minimal cost, but speed is limited and debugging is an art. Modbus TCP moves the same register model onto Ethernet: faster, routable and directly readable by platform software.

Real projects use both: legacy meters speak RTU, new remote I/O (like the ADAM-6017) speaks TCP/MQTT natively, and a gateway or protocol-converting router bridges them into one platform. KIES quotes acquisition solutions on this structure by default.

## Enquiries and technical support

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- Enquiry form: https://www.kies.com.cn/en/contact
- Email: ai@kies.com.cn
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