USB to RS-232 adapter hacked to use RS485 instead

[André Sarmento] needed to connect a computer to an RS-485 bus. A simple converter can be sourced online, but the only thing he could find locally that was even close was a USB to RS-232 converter. He used that component to craft his own USB to RS-485 bridge.

RS-485 is often used for remote sensors as it provides a method of connecting electronics over long distances. The converter which he started with seems to be encased in a hot-glue-like substance. A bit of time with a torch and he was able to get to the components on the board. There are two stages, one which converts RS-232 to TTL, and the other converts TTL to USB. [André] removed the RS-232 chip and patched his own board (shown on the left) into its TTL lines. He was also able to add a few more configuration options, like using an external power source, and having a few jumper-selected resistor options.

5 thoughts on “USB to RS-232 adapter hacked to use RS485 instead

  1. 22 days from china, I know, I order a $1, free shipping, buy-it-now item every day.
    Anyhow, I wanted to point out an article error, feed to a 7805 must be 7.5V** min to get 5V out.
    ofcourse you all know this, I’m sure it was just a typo.
    ** all numbers in my statement are approximate **

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