We use the ADM2587E in our current product design. We have noticed intermittent RS485 errors when communicating at high baud rates (115200), over short distances (<2m) with no termination resistor present.
In production our devices always operate with a 120R termination resistor at each extreme, but in isolation it would be expected that an individual device should communicate without the need for a termination resistor. Below is the circuit diagram for our 485 interface.
Below are the scope readings for the A-B signal firstly with no termination, and with 120R termination.
Notice the double dip at the start of every returned message.
This does not appear on the previous design (shown below without termination), or when 120R termination is used.
Thanks for any help you can offer.