# RS485 Pi

**Type:** Product page · **SKU:** CE07496 · **Brand:** [AB Electronics](https://core-electronics.com.au/brands/ab-electronics-australia) · **GTIN:** 7426787870163
**Page:** https://core-electronics.com.au/rs485-pi.html ([markdown](https://core-electronics.com.au/rs485-pi.html.md))

The RS485 Pi is a communication board supporting the RS-485 serial protocol.

## Pricing

- **Price:** $28.95 (inc GST) — $26.32 AUD, exc GST
- **Quantity discounts:** 10+ $25.26 (exc GST) · 25+ $24.47 (exc GST)

## Availability & dispatch

- In stock, ships same business day if ordered before 2PM (Australia/Sydney).
- We can dispatch 4 today; more stock is typically available with a 10–14 day lead time.

## Description

The RS485 Pi is a communication board supporting the RS-485 serial protocol.

The RS-485 port is connected to the UART port on the Raspberry Pi using a SN65HVD72 interface. The SN65HVD72 IC converts the 3.3V UART signals to RS-485 voltages allowing communication with RS-485 compatible devices over a DB9 serial cable or twisted pair cable. The RS-485 port can be accessed through the DB9 port or the solder points on the PCB.

The RS485 Pi contains protection against voltage spikes in the form of a TVS Diode and two 10-Ω, Pulse-Proof Thick-Film Resistors.

Please note that you can only use one RS485 Pi board on a Raspberry Pi. if stacking with other boards we recommend putting the RS485 Pi at the top of the stack due to the height of the DB9 connector.

Using RS-485\*You need to use the latest Raspbian Jessie release and disable the built in Bluetooth to use the RS485 Pi on the Raspberry Pi 3, [see our KB page for the config changes needed.](https://www.abelectronics.co.uk/kb/article/1035/serial-port-setup-in-raspberry-pi-os)

RS-485, also known as ANSI/TIA/EIA-485, TIA/EIA-485 or EIA-485 is a standard used in serial communication systems. Equipment using the RS-485 standard can be used over long distances in noisy environments. Unlike RS232, the RS-485 standard allows for multiple devices to be connected on the same network. The recommended arrangement for connecting devices to an RS-485 network is to use a series on nodes connected along a line or bus with terminating resistors used at either end of the bus to reduce reflections.

A 120-Ω resistor is included with the RS485 Pi which will need to be fitted if the board is connected to the end of the RS-485 bus. The diagram below shows a typical network of RS-485 devices.

![rs485network-ce07496](https://core-electronics.com.au/media/wysiwyg/rs485network-ce07496.jpg)

**Specifications**

- Supply Voltage: 3.3V
- Logic Voltage at GPIO Port: 3.3V
- Differential Input Voltage at A & B: -12V to +12V
- High-level input voltage: 2V
- Low-level input voltage: 0.4V
- Signalling Data Rate: 250 kbps
 
**Documents**

- [RS485 Pi - 3D CAD File (STEP Format)](https://core-electronics.com.au/attachments/localcontent/rs485-pi-1_54099e816ce.zip)
- [Schematic Drawings](https://core-electronics.com.au/attachments/localcontent/schematic-rs485pi_163086760a9.pdf)
- [Datasheets](https://core-electronics.com.au/attachments/localcontent/sn65hvd72_15199c15dc9.pdf)

## Images

- [Product image 1](https://core-electronics.com.au/media/catalog/product/r/s/rs485pi-1.jpg)