Identify data protocol

Other Hardware Device Hacking
1

Hi
I have a Thule AV100 that is able to control a Thule PA350B trough a ethernet cable (RJ45 plug in each end).
Measuring the output from the AV100 shows:
3.3V on the RJ45 pin 1 and 2 over 8 (gnd)
9.8V on the RJ45 pin 5 and 7 over 8 (gnd)
0V on the RJ45 pin 3, 4 and 6 over 8 (gnd)
It seems like pin 1 is data and pin 2 is clock.

This is from the doc of the AV100.

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How may I observe what signal is sendt from the AV100 to the PA350B to control it?
And how may I use the same signals to control the PA350B from an aurdino instead of from the AV100?

2

To observe you will need an oscilloscope. If I understand your question, you will need a UART library to do what you want.

3

It appears that pins 1 and 2 would be used for communication between the devices. Get a logic analyzer and connect to pins 1, 2 and 8 and see what the signals look like. A $10-$15 USB 24MHz/8 channel logic analyzer (use that for the search term) should be fine. Available from the usual sources or Amazon or ebay.

1 Like
4

Do you have any documentation that tells you the control information that uses the bi-directional clock and data on pins 1 and 2 are duplicated on the RS-232 connections? That would be critical information if you want to observe the signals/message data.

5

the simpliest way, as it was already mentioned is to use cheap 8channel logic analyzer. So you can identify clock & data pins. Once identified, things get much simplier :))

6

I'll hazard a guess that clock and data are on pins 2 & 1.... :grinning:

7

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