Here is what I can tell you. Same LINK as Frigates currently have. No CEC because there are no effectors on JSS (it doesn't operate offensive weapons only self defensive ones). JSS is expected to act as TG commander in some cases. So all the comms and data sharing are very robust.
What is new on JSS is LINK Space and Land track capability, which was added to the program's CMS 330 contract. The reasons for this are twofold. First JSS is designed to support to forces ashore in a permissive environment (read humanitarian operations). The second is that this development drives CMS software development out of a different budget, which will eventually be implemented into the frigates and CSC CMS systems.
The end goal is to have a single CMS "suite" and when you install it on a ship you can pick and choose the options. JSS, CSC and CPF's will all have different weapons and sensors, so upon installation you just select the groupings that are pertinent to that particular platform. This will significantly reduce costs as the entire CMS suite can be controlled under a single contract and version.