Wouldn't RS485 need two pairs (4-wire)? But maybe since this is most likely only sending from the remote to controller maybe one pair. IS there a way to decode the 2 wire RS485 on the scope?
Just two wire as others said. A & B are your differential pairs and the setup would be half-duplex for communication. You can probably just probe either A or B unless you're at the end of a long run with some noise. Then you can probe A on CH1, B on CH2, and subtract them to get the differential signal. Or as others have said, probe the otherside of the RS485 transceiver itself.
As for decoding you could probably tap the line as others have said, run the remote straight to a RS485 USB dongle and capture, use a logic analyzer, or just count the bits on your scope.
For example, below is the letter 'U' (0x55 - 01010101) being transmitted.
The yellow trace (CH1) is the A line.
The blue trace (CH2) is the B line.
The purple is a differential (B-A) of the two.
rs485_SN65LBC179P by
smerrick, on Flickr
I've written up some stuff on avoiding cheap RS485 dongles
here if interested. Performance can be dodgy at best on some of them.