Re: [tlug] Can't get a response from a serial usb device (trying to talk to a Japanese electricity meter)

[Christian Horn <chorn@example.com>]

On Mon, Sep 22, 2025 at 04:26:37PM +0900, Edmund Edgar wrote:
> I'm trying to get power readings from my electricity meter. My plan is to
> use that information to hit the API of my EV charger (which I haven't
> bought yet) to regulate how much power it tries to pull and avoid drawing
> more than my allotted amperes and plunging my house into darkness.
> 
> Apparently the meters will broadcast their current load on something called
> a HAN, a system they call B-Route. This is aimed at HEMS devices which
> you're supposed to buy from a professional but I'm a Linux user so that's
> not how I do things, so I filled in the form for TEPCO to send me the
> username and password for the meter and they did.

Cool stuff, these terms ring a bell.
I had started to play with SDR for being able to read my
smart meter, and then realized the same protocols/scheme used in your
place are used here.  The data is encrypted and I understood I could
request to register to get the keys to read via B-route, but never
did that.


> But it doesn't seem like I'm managing to read anything back from the USB
> dongle at all. [..]

I would start minicom and screen as client programs, various baud
rates, parity settings.
wireshark could also be used to sniff on the usb level and might give
hints.

Christian