Hello Ken, Thanks for the email. Let me answer your last line first - We cannot implement the EtherNet/IP stack on the Third Party Device as it is a Black Box for us and cannot be changed. We have the documentation and communication protocol for that unit. Based on your reply we need to use the "1756-EWEB, 1768-EWEB, and the newest CompactLogix 5370 series controllers" for a "open socket feature". Thanks for the same. Moreover as I had mentioned initially the communication has to be deterministic (every 20 ms to 9 such similar third party devices). We shall read the datasheets of the products but if it is quickly possible for you to answer - Is such deterministic communication possible using these devices? Really appreciate the time and efforts that you are taking to reply to our query. Thanks and Regards -Ajay