RS485 Optical Isolator

Optical isolator supports bi-directional "half-duplex" transmission for RS485 networks. Optical isolator protects TapHome control unit when connecting Modbus RTU or other RS485 bus device to it. Use of optical isolator is obligatory if one of the conditions is met:

  • External device is powered by other (typically its internal) power source and does not have galvanic or optical isolation
  • TapHome module or other RS485 device device is connected to TapHome BUS, and the wire or device itself is outside of the lightning protection. This is the most common situation when when connecting TapHome modules in the garden house, or meteo station on the roof. In this case, also power source must be galvanically isolated - the easiest way is to use separate power source.

SLAVE side is external device MASTER side is protected device, typically TapHome Core control unit

The isolator must always be installed on the side of one of the protected devices (MASTER) - as close as possible to it.

In order to achieve protection, SLAVE device must be powered by other power source than MASTER device (TapHome Core and Modules).


  • 2-way half-duplex transmission
  • Baud rate up to 1Mbit
  • Very fast switching of transmission way with 1 bit resolution, regardless of the data rate
  • Indication of data transfer via LEDs, with distinguishing of direction
  • Protection against overvoltage - SLAVE side, protecting against a surge induction


  • Power supply: 9-24V AC/DC
  • Current consumption: max 60mA
  • Separation level: 1kV DC
  • Surge protection: Power supply + SLAVE RS485, 600W @ 8/20μS
  • Transmission mode: 2-way, half-duplex
  • IP class: IP40
  • Ambient temperature: -20-60ºC
  • Dimensions: 74 x 32 x 25 (mm) with terminals

RS485 Optical Isolator

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