[gstar]

Oh, and you just need one of these and a TTL to RS422 converter off aliexpress to replicate the interface:

https://www.aliexpress.com/item/1005005918675239.html

The connectors on the small RJ45 daughter board are JST-SH 1.0

The yellow lead puts out 4.2v to replicate a Li-Ion battery (as far as I can tell). You can ignore this.

Red is positive

Black is negative

Green is usb d+

Blue is usb d-

[ranebo]

This is all fantastic info. I have included the details and a link to these comments at the bottom of the post. Great work!

[lucioperca]

Tip: Instead of soldering I use splicing connectors with levers for testing stuff like this out. For example:

https://www.wago.com/de-en/c/installation-terminal-blocks-an...

[saylisteins]

Tiny QOL change without too much work, you could install something like teamviewer on the tablet, and now you're able to control your AC remotely from your PC, your phone, or anywhere!

[Nursie]

Hey - As the owner of a similar system I have a question for you - do you use their phone app to control your system from your phone in/out of the house, and did it still work after this?

[nehz]

Would you have the RJ45 pinout too? Thanks!

[FLT8]

This is from my earlier notes, hope it helps some.

  Pin 1: RS422 +/B
  Pin 2: RS422 -/A
  Pin 3: ? - appears to be unused; connected to unpopulated pad on PCB
  Pin 4: GND
  Pin 5: ~14.2v DC unloaded
  Pin 6: GND
  Pin 7: ?
  Pin 8: ?
  Shield: GND

Note: the RS422 protocol has a basic bus arbitration built-in to allow both ends to communicate. The control unit sends <U>Ping</U=xx> messages, after which it opens a slot for the Tablet to communicate back to it. At least on my system xx represents a simple CRC value that can be used to validate message authenticity. I haven't seen any AES encryption in use, messages I've seen are all plaintext, maybe the AES encryption was introduced in a later revision.

[gstar]

No, sorry - I may be able to buzz one out of the a/c controller later on.

I do, have 2 spare USB-C to JST-SH adapters that suit the round advantage air circuit board if anyone wants one (Perth, Free). Email in profile.