Trouble identifying pinout

[abqa]

I have a air conditioner that has a header on the mainboard that various optional (expensive) addon communications modules can connect into eg wifi

I am wanting to see if I can connect to this port and control it over serial or similar once I determine what protocol it is using. RS232?, RS485?
I have been trying to determine what protocol this port uses to communicate with the addon modules that can be plugged into it and what the correct connections are. Once I have determined the correct pins and protocol I should be able to write a script that will do the communication.

I have done some research and probing with multimeter (I don't have an oscilloscope currently ) and located a circuit diagram for the header on the mainboard (attached),

What i have determined so far:

Pin 1 0v  - possibly rx?
Pin 2 5v  - possibly tx?
Pin 3 5v  - possibly tx?
Pin 4 12v
Pin 5 Gnd

I was wondering if anyone has any suggestions or pointers on what I could try to work this out?

[Jwillis]

USB http://www.hobbytronics.co.uk/usb-connector-pinout

[abqa]

USB http://www.hobbytronics.co.uk/usb-connector-pinout

Thanks Jwillis, Can you help me understand what lead you to believe it is USB?

From the reading, research I have done and pin voltages I believe it is unlikely to be USB.

[Nusa]

I'd be more likely to guess I2C, especially if more than one device can be attached/chained off that. You're more likley to figure it out if you actually have one of those add-ons and some method of monitoring the obvious data lines (pins 2 and 3).

You've committed the classic sin of failing to give us basic information that you have, such naming/linking the brand and model info on the air conditioner and the add-ons you're trying to emulate. That severely limits the ability of anyone to acquire the answer for you.

[abqa]

Thanks Nusa

It is a Panasonic Split system from the CU/CSZ20TKR range (however this connector is common across many of the panasonic series)
My understanding is only one addon can be connected at any time (not 100%sure about this)

Modules available include:
CZ-TACG1 Wifi kit: http://www.panasonic.hk/usm.ashx/e/7zt1rwYXAiWEX1X3Hkyy9Naxy7NSnBFA89YBELQe-2L0J2RMcxQSCsgXytHbtm7ZBFLpQZ8phzb451XTOV_fX3-xb7Vrxt1ft7KR-ODzZh6hNYcPgXEggCffw1CXZUluSh5e~UC~0Hc00GxCOL1ctdmAe6NNFvzxYL30cW-4zk8o/CZ-TACG1-WiFi-adapter-users-maunal.pdf
IntesisBox PA-AC-BAC-1: https://www.intesisbox.com/intesis/product/media/intesisbox_pa-ac-bac-1_installation_manual_en.pdf?v=2.1
Panasonic PAW-SERVER-PKEA - https://www.panasonicproclub.com/uploads/IE/catalogues/II_PAW-SERVER_PKEA_v44_EN_2013.pdf

Unfortunately I don't have any of these available for testing with