Google Chrome Web Serial API: How do I address a Modbus device with a hex code?

It is my intention to address a device with Modbus via the Web Serial API built into Google Chrome. I want to address my device with a HEX code. The following screenshot proves that my device can be successfully addressed with a tool like this. enter image description here The interface is thus addressed with the following hex value: 01 03 00 01 00 02 95 CB

My question now is. The Tutorial only shows how to address the interface as Uint8Array or Text. How can I address the interface with a HEX code?

Thanks for the help