I'm assuming you're asking in reference to the Internal Router from Chrome Flesh.
So first off, yes, there is no capacity cost, so you can only get it by paying for it with Essence. The purpose of the internal router is to connect various pieces of 'ware together to be able to utilize their wireless bonuses without them actually broadcasting wireless. The best example I van think of is the synergy between Wired Reflexes and Reaction Enhancers.
Now, you might notice that it isn't super well defined, indicating that only works with wireless bonuses that don't explicitly require a network connection, but doesn't give a good way to determine which items qualify on that caveat specifically. It's a best judgment call, but the rule of thumb is if the bonus mentions needing to collect data from outside sources, it is probably not one that works through the router.
Now, all of that is specifically for helping route and get bonuses from your cyberware without needing to have them subscribed through your PAN. There isn't any equivalent item for non-cyber, because that is what your commlinks is for, which means it is on your PAN.
The closest you could get is a GM allowing you to get some of the similar abilities when you run a hardwire connection from your devices, but you're still probably going to have your commlinks active so it doesn't really give you a bonus or anything.