Getting a PCB manufactured was one of those steps that felt bigger than it probably should have.

Up to that point, almost everything could still be changed instantly.

If the schematic was wrong, I could fix it.

If a footprint was wrong, I could replace it.

If routing looked bad, I could move things around.

Once I placed the order, that changed.

Now I had committed the design to actual copper, fiberglass, solder, components, and money.

I used JLCPCB for manufacturing and assembly, which meant I also had to learn a whole new set of details around BOMs, part availability, assembly options, component substitutions, board files, and what the manufacturer actually needed from me.

That was another part of the project I had never dealt with before.

In the PLC world, if I need a controller, an input card, or a relay, I usually buy a finished product that already exists.

Here I was the one creating the finished product.

When the first boards finally arrived, I remember looking at them and thinking they looked far more professional than I expected.

It was strange seeing something I had been staring at in EasyEDA suddenly sitting on the bench as a real assembled PCB.

Then the excitement wore off and the real test started.

Does it power up?

Is 3.3 volts actually 3.3 volts?

Is the ESP32 alive?

Is the MAX3232 doing anything?

Are the signals going where I think they are going?

Does the DB9 behave like the schematic says it should?

This was the point where I stopped being able to solve problems by moving things around on a screen.

Now I had to measure them.

I started checking power rails and signal paths and eventually confirmed that the RS232 side was producing real RS232-level voltages.

That was a good sign.

It also did not mean the board actually worked.

That distinction became important pretty quickly.

The board could power up, the ESP32 could run, the transceiver could generate the right kind of voltage, and communication could still fail.

That ended up leading into one of the more useful debugging lessons of the entire project.