# Modbus TCP / Modbus RTU Gateway
**URL:** https://discourse.nodered.org/t/modbus-tcp-modbus-rtu-gateway/26967
**Category:** General
**Created:** [20 May 2020 06:25 UTC](https://discourse.nodered.org/t/modbus-tcp-modbus-rtu-gateway/26967 "2020-05-20T06:25:15Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@Chris1](https://discourse.nodered.org/u/Chris1)
#### Post date: [20 May 2020 06:25 UTC](https://discourse.nodered.org/t/modbus-tcp-modbus-rtu-gateway/26967/1 "2020-05-20T06:25:16Z")
Hi I'm new to node-red. I need to boild a gateway for Modbus. My home control system has a Modbus TCP connector and my ventilation control system uses Modbus RTU with an RS232 interface.
What works so far:
- Raspberry Pi with RS232 Interface and Node-Red installed
- Read / Write registers on ventilation control system with RS232 and Modbus RTU using Modbus Flex Getter and Modbus Flex Write
- Write results in Modbus TCP Server
- Read Values from home control system (using CAS Modbus Scanner)
I didn't figure out how to pass the client request (read/write) from my home control systen (Modbus TCP) directly to the Flex Getter or Flex Write. I didn't find any trigger in the Modbus TCP to indicate that a new request has taken place.
Help is appreciated.
BR Chris
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### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [19 July 2020 06:25 UTC](https://discourse.nodered.org/t/modbus-tcp-modbus-rtu-gateway/26967/2 "2020-07-19T06:25:23Z")
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