# TTL to RS485, UART, 3.3-5V converter module

> TTL to RS485 converter module, UART, operates at 3.3-5V DC. Allows connecting a microcontroller to an RS485 bus, supports up to 128 devices, features RXD/TXD LEDs, a 120 ohm termination resistor activated via R0 jumper, and external grounding option. Operating temperature -40 to +85 degrees C, recommended transmission distance up to 800 m without repeaters. Suitable for automation and industrial control.

- Page: https://sigmanortec.ro/en/ttl-to-rs485-uart-33-5v-converter-module
- Price: 14.24 RON
- Availability: In stock; 1-2 zile
- Reference: 9971 · EAN: 5940948294145
- Category: Mechatronics and IoT > Serial and CAN Converters
- Specifications: Input Voltage: 3.3 - 5 V; Input Voltage Type: “DC” in Romanian can mean **“de ce”**, which translates to **“why”** in English.
- Package (shipping data): 0.004 kg
- Updated: 2026-09-14
- Shop: [Sigmanortec.ro](https://sigmanortec.ro/en/llms.txt)
- Prices: RON, VAT included; prices and stock as of 2026-10-22 01:37 (Europe/Bucharest)

## Description

Allows quick connection of a microcontroller to an RS485 bus via UART TTL, ideal for automation and industrial control over long distances. Operates at 3.3V or 5V, offers anti-interference protection and external grounding for harsh environments, supports up to 128 devices, includes RXD TXD LEDs and switchable 120 ohm termination resistor.
TTL to RS485 converter module that allows microcontrollers to be interconnected with RS485 industrial networks, making it ideal for automation applications, remote control and industrial systems. This adapter also features protection against electromagnetic interference (anti-jamming), making it suitable for use in harsh environments and over long distances.
It is compatible with both 3.3V and 5.0V power supplies and supports UART communication with up to 128 devices on the RS485 bus. For transmissions longer than 800 meters, the use of RS485 repeaters is recommended.
The module has 120Ω termination resistors (enabled by shorting jumper R0), LEDs for RXD and TXD signals, as well as a special design for external grounding, providing protection against electrical discharges and signal interference.
Technical specifications:
Power supply voltage compatibility: 3.3V and 5.0V
UART interface: compatible with TTL signal 3.3V/5.0V
Operating temperature: -40℃ to +85℃
Transmission distance: up to 1 km (with 850 m F1.5. Recommended up to 800 m without repeaters)
Protections: anti-interference protection, anti-lightning, grounding design
Device support: up to 128 nodes in the network
LED indicators: RXD and TXD for monitoring data traffic
PCB design: semi-hole, thickness 0.8 mm, pitch 2.54 mm
Termination resistor: 120Ω, selectable (jumper R0)
External ground connection: for increased safety in outdoor applications
Pinout:
Use:
Connect the TX, RX and GND pins of the module to the microcontroller.
Connect lines A and B to the RS485 network.
For protection against interference and lightning, connect the GND pin of the module to ground.
Activate the termination resistor (R0) if it is the last device in the network or at long distances.
Observe the RXD and TXD LEDs to check the transmission status.