# I2C Modbus RS232 Slave Module (IS4310-232M5)

Give any microcontroller an RS232 Modbus RTU slave port. Your code only reads and writes 500 registers over I2C.

- **Seller:** [INACKS](https://www.lectronz.com/stores/inacks), Terrassa, Barcelona, Spain
- **Price:** €4.54 (EUR, before shipping and taxes)
- **Availability:** In stock
- **Categories:** RS232/RS485, I2C, Components
- **Country of origin:** Spain
- **Product page:** https://www.lectronz.com/products/i2c-modbus-rs232-slave-module-is4310-232m5

## Links

- [Documentation](https://inacks.com/wp-content/uploads/IS4310-Datasheet-I2C-Modbus-RTU-Slave-ISDOC125.pdf)

## Images

![I2C Modbus RS232 Slave Module (IS4310-232M5)](https://lectronz-images.b-cdn.net/lectronz/active_storage/representations/proxy/eyJfcmFpbHMiOnsiZGF0YSI6NzU4NDMsInB1ciI6ImJsb2JfaWQifX0=--a8b9152dd0143cd3ad299bc7c0f82abd977d87e7/eyJfcmFpbHMiOnsiZGF0YSI6eyJmb3JtYXQiOiJqcGciLCJyZXNpemVfdG9fbGltaXQiOls5NjAsNjQwXSwic2F2ZXIiOnsic3RyaXAiOnRydWV9fSwicHVyIjoidmFyaWF0aW9uIn19--970c165836a83091725a1a0fd4f37ce9408da1bf/IS4310-232M5%20INACKS%20Modbus%20I2C%20RS232%20Slave(1).jpg)
![I2C Modbus RS232 Slave Module (IS4310-232M5)](https://lectronz-images.b-cdn.net/lectronz/active_storage/representations/proxy/eyJfcmFpbHMiOnsiZGF0YSI6NzU4NDcsInB1ciI6ImJsb2JfaWQifX0=--358fc6b839809fd169bfbe8ec27be6a85e3ecf6a/eyJfcmFpbHMiOnsiZGF0YSI6eyJmb3JtYXQiOiJqcGciLCJyZXNpemVfdG9fbGltaXQiOls5NjAsNjQwXSwic2F2ZXIiOnsic3RyaXAiOnRydWV9fSwicHVyIjoidmFyaWF0aW9uIn19--970c165836a83091725a1a0fd4f37ce9408da1bf/IS4310-232M5%20INACKS%20Modbus%20I2C%20RS232%20Slave(2).jpg)
![I2C Modbus RS232 Slave Module (IS4310-232M5)](https://lectronz-images.b-cdn.net/lectronz/active_storage/representations/proxy/eyJfcmFpbHMiOnsiZGF0YSI6NzU4NTEsInB1ciI6ImJsb2JfaWQifX0=--ff7ffa15afe66d18fee955381acd3555152ac461/eyJfcmFpbHMiOnsiZGF0YSI6eyJmb3JtYXQiOiJqcGciLCJyZXNpemVfdG9fbGltaXQiOls5NjAsNjQwXSwic2F2ZXIiOnsic3RyaXAiOnRydWV9fSwicHVyIjoidmFyaWF0aW9uIn19--970c165836a83091725a1a0fd4f37ce9408da1bf/IS4310-232M5%20INACKS%20Modbus%20I2C%20RS232%20Slave(3).jpg)

## Description

[**IS4310 Datasheet (PDF)**](https://inacks.com/wp-content/uploads/IS4310-Datasheet-I2C-Modbus-RTU-Slave-ISDOC125.pdf)

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## Overview

Need a Modbus RTU slave on RS232 without writing the protocol yourself? This module puts the IS4310 Modbus chip, an RS232 transceiver and a female DB9 connector on one small board. The chip deals with frames, CRC and timing. Your firmware just reads and writes registers over I2C, and the PC, PLC or HMI on the DB9 side sees the same 500 Holding Registers.

## Key specs

- 500 Holding Registers shared by the I2C and Modbus sides
- Function codes 0x03, 0x06 and 0x10
- Defaults: Slave ID 1, 19200 bps, Even parity, 1 stop bit (all changeable)
- I2C address 0x11, speed set by the I2CSPD pad: 100 kHz, 400 kHz or 1 MHz
- 3.3 V supply, 5 V tolerant I2C lines
- Six castellated pads for direct soldering or pin headers
- Straight-through DB9 cable to the master (not crossed)

Works with Arduino, STM32, Raspberry Pi or any MCU with I2C.

## Shipping policy

We ship all products from Barcelona via UPS within 1–2 business days. A tracking number is provided. Transit time is typically less than one week worldwide (excluding handling time).