Hello Milind Raval,
I'm not sure I understand your question here--are you asking if Opto 22 has a hardware equivalent of what the Modbus Integration Kit does? The answer to that is: No. However, just to be clear, remember that both the SNAP-PAC-S and -R series controllers have built-in Modbus TCP/IP support as a slave. So if you have a master elsewhere, the -S or -R can be the slave device with no extra hardware/software required.
What the Modbus kit allows you to do is turn an -S or -R (or even SoftPAC) into a Modbus MASTER so it can then control non-Opto 22 Modbus slave devices.
Here's a nice overview (click here) of Modbus (and other protocol) integration options that are either build-in or available through a kit.
I hope that helps!