Do I Need A New Power Supply?

[Guest]

You are quite right Georg, RS485 looks for 120Ohms and two 680Ohms in parallel is 340Ohms, so I'm not quite sure how it works on the Galaxy.....but it does!!

not sure if they really wanted to invent it again. it is actually SOOOO simple that it should be perfect as it is. it only works on principle that if voltage is higher in A than in B it means "1" and if voltage is higher in B than in A it means "0".

anyhow i had a similar kind of problem with another alarm panel and changed the RS485 chip with better one on the PCB and voil