Framing error on Rx line in rs485 to ethernet converter
What resistor do you refer as the termination? The 1 kOhm resistor is still way to much for RS485. If the twisted pair is your media (as it should be), resistors should be around 120 Ohms (100 to 150 Ohms) between the lines. Of course, this should be arranged only at the connection endpoints. Is it possible that your ATC1000 which is working just have those resistors, and in other case they are not present (and you 1 kOhm is not a proper termination).

You migh also want to try some 10 kOhm resistors from each line to the ground. It is not termination, but helps keeping the noise on the lines down when there is no transmission (so that receivers would not get false signal triggering UARTs).

I have also had the case of going 'too fast' into reception mode (when working in half duplex), so that my firmware would cut off part of the message. It was resolved by having receiver on all the time so that my sender would actually 'see' everything that went down the line when transmitting. If that was not the case I would have to arrange for some delay before starting receiving, and delay could be to long so I could miss the start of the message.