unknown serial protocol - (RS-232. 422 pLAN ) ??

Half duplex RS485 at a guess.

..... can you trace the tracks back to a line driver?

I tried to, and looked for a MAX232 IC but no luck, they go back into the Micro above the connector, my guess I2C, giving that the cable is daisy-chained to each of the coolers

any guess on how i maybe able to sniff the data out of it?

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at

X+

Yup, looks like RS-485. Try using up a MAX1483 in receive mode... Hope that helps, Best Regards, Dave

maybe this ?

om...

what

RX+

Cool Guys! really quick replay! It's looking more like a RS-485 I'll do up a RS-232 circuit to RS-485 and get it connected to a pc, that said, it's been a while since i've done some electronics, any new apps out their to detect BAUD rate, party, stop bit, etc..

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at

X+

I see the connector, but I can't trace the pc connections. If you say it goes to the MCU, I'll take your word for it.

RS-485 is spec'd as a 5 volt differential interface with tri-stated driver outputs. This allows the two wires to function as both tx and rx. If you want to "sniff" it, you can just look at the TX+/RX+ signal. You will likely see it at +5 volts normally and brought low when a transmission is made. With a scope you can figure out the baud rate and the configuration (parity, data bits, stop bits). To monitor the line, you can drive an RS-232 driver with this signal and then to a PC.

Rick

snipped-for-privacy@m40g2000yqh.googlegroups.com...

Not all driver chips are MAX232 -- find out what's driving those lines, and you're a long way to finding out what the physical layer is, if not the protocol.

Darragh schrieb: ...

A scope.

Falk

As someone already suggested it looks like RS485 would be a good guess to start with. Try hooking in an RS485 converter to your PC and scope between the lines with a differential probe to see what the traces look like as you try to elicit activity from it (ENQ is always a good first prompt character to try). This way you may discover the baud-rate and what the device is sending in response to your prompting. Once you begin to have a dialogue things should become clearer.

Alternatively, can you not find the manufacturer of the coller board and just ask them for the protocol details?

Note to the OP that the RS-422 & -485 "A" side is mark (idle state) low with respect to the "B" side. It's not at all uncommon for the labels to be reversed so it may be worth flipping the connections if the PC reports gibberish.