Wiznet WIZ750SR and Modbus

Attempting to use the WIZ750SR (RS485) to communicate to a Modbus device. My other RS485 converters work fine. I can monitor the sent packets, and when I send them with the 750SR, there is no reply.
This is usually due to the character timing. Modbus is very strict. I do not see a way to adjust the character timing and spacing.
Has anybody had success with this device on Mobus over TCP?

What firmware did you use?
Unfortunately, there is no example of implementing Modbus with WIZ750SR.
This link contains code that implements Modbus on the WIZ550S2E module. I hope it helps.

Firmware is version 1.2.4

Trying to find applicable notes in link.

Thank you.


Seems to be a bit beyond my capabilities.
I’ve used quite a few convertors, but I haven’t done his type of programming before.
I am assuming that this will not download to the 750.

Any hints would be appreciated.