DIY Fohhn-Net NA-11 Converter Alternative

This article is about building an “USB to Fohhn-Net Converter” for Fohhn Audio devices for 2 € (instead of paying hundreds of Euros for the Fohhn NA-11 converter).

Fohhn Net is based on RS-485, which is a simple standard for data transmission. So all you need is a USB to RS-485 interface – and a simple physical connector for your Fohhn hardware.

There are multiple ways to connect Fohhn hardware to Fohhn Audio Soft – depending on the Fohhn device:

  • USB-C connection
  • TCP-IP connection
  • RS-485 connection

This guide is only for RS-485 connection.

RS-485 to USB interface

You can find thousands of such RS-485 to USB interfaces online.
I just picked this one for 1,80 €.

Physical connection to Fohhn hardware

Fohhn Net connectors could have XLR or RJ-45 connectors. Our device (Fohhn Amp DI-4.1000 with analog XLR input interface) has a RJ-45 port for RS-485 Fohhn Net. So we have to build a small adapter for that.

Fohhn Net Documentation shows how to connect the RS-485 Pins to RJ-45 Pins.
Sometimes DATA+ is also called A, DATA- is called B.
Using T568B it’s connected to the blue and green cables.
Using T568A it’s connected to the blue and orange cables.
Cat.7 network cable connected with RS-485 USB module.
RJ-45 Fohhn-Net connected with Fohhn amp

Fohhn Audio Soft

We have to add the RS-485 connector as Fohhn Net Node in Fohhn Audio Soft.

Open Fohhn-Net Settings
Add node, select “Fohhn-Net USB Adapter (USB)”
Select your USB device

That’s it! No you can manage your Fohhn Devices via Fohhn Net.


Using an own RS-485 USB adapter is your own risk. There is no guarantee that it’s working or it will not destroy your Fohhn hardware.

I’m using it in a church to remotely manage Fohhn DI-4.1000 amps via network cabling.


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