I put together the circuit for transmitting dmx using a MAX485 chip ( I noticed that all the wiring examples used 75176 chips, does the max485 have different hook-ups?) on a breadboard. I have it hooked up using a 3-pin cable to a 4 channel dimmer pack with some incandescent lights. I have tried both examples from the dmxsimple page and there is no response from the dimmer pack. Here's the weird part: if I unplug the transmit line from the arudino to the chip the light turns on 100%. Also, I hooked up two leds in a dmx-tester configuration and they don't seem to indicate any traffic (one stays lit constantly).
I've tried rebuilding the whole circuit using different chips and it still wont work at all.