I don't understand your question. The MAX485 is a chip from Maxim. If it is from another brand, it is not a MAX485. Something like the ST485B might be compatible (didn't check), but it is not a MAX485.Maxim sells it in at least three packages: DIP, SO and µMAX. The latter is a proprietary format that is specific to to Maxim: http://electronics.stackexchange.com/questions/15839/what-is-%C2%B5max-ic-packageIf you buy the chip as DIP or SO, you get the top layout, if you buy it in µMAX, you get the bottom layout.
i was able to work out my chips are DIP by looking back at the store listing where i got them.
I have spent all day trying to get two max chips to talk to each other. If my circuit is correct it must be a software issue.
That makes no sense. You only have to look at the chip.Does it look like this:1. DIP8or like this:2. SO8or like this:3. µMAX?Note that 2. and 3. look similar on first glance, but they are different. E.g., the legs are much closer in 3.If you chips are DIP, you have to stick them through your PCB to mount them (or in a socket). 2. and 3. are surface mount.
Can you post your circuit so we can see how you have connected the chips and if your controlling the ~RE/DE from the Arduino (instead of tying to VCC/GND) maybe also post your code.