USB to TTL serial cable with RS485

Hardware
1

Hello all,

Does anyone know if it’s possible to use a USB to TTL serial cable for RS485 protocol?

The cable in question:

I would like to use above mentioned cable with Infinity integration on Bryant furnace without buying USB to RS485 serial converter.

Reading through, Rpi requires USB to RS485 serial converter.
I only require RX/TX pins TTL does support up to 3.3V, while RS485 recognize any differential voltage >200mV with a voltage range of -7V to +12V.

I guess I am answering my own question if anything over 3.3V will damage.

This is my go to cable for flashing sonoffs and don’t want to destroy it.

Thank you all,

2

It’s been awhile, and not for Home Assistant, but from some work I was doing programming PLC’s bit I use a USB to RS-232 converter and then this device:

HXSP-485B RS-232 To RS-485 Converter
https://www.hexin-technology.com/RS-232_To_RS-485_Converter-Product-257.html
looks like USD 18 on ebay today, don’t remember what I paid
so that price plus a ‘regular’ USB to RS-232 cable

3

Thanks, If this cannot be done, most likely will get USB to RS485 converter. Indeed they are cheap these days.

4

Good hunting…the key question I ask myself before I plug in any ‘Serial’ device be it TTL, RS-232, RS-485, RS-#$%$##$# is what are the voltages? This message comes from my drawer of ‘fried’ devices :wink:

1 Like
5

how can I use a sensor connected to this convertor.