With a reported screen resolution of 720 x 1280, this 7" phablet is taller and skinnier than the Galaxy Tab 4 7.0. It's listed as running Android 4.3 on a quad-core 1.2GHz CPU with 1.5GB RAM, 8GB Flash storage, Wifi, and Bluetooth.
That actually sounds quite a bit like the Tab 4 7.0 (aside from the boost in RAM), but there are also some differences. The SM-2558 has much better cameras than on Samsung's budget tablet (8MP and 2MP). This phablet is also listed as being lighter than the Tab 4 7.0 (245g vs 276g.)
And this device sports TD-LTE and TD-SCDMA connectivity, confirming that it truly is a phablet.
At this point you might be wondering whether this is the Galaxy Note 4. Recent leaks have suggested that Samsung has another Note phablet in the works, but all we have so far is the name. But in spite of the curious coincidence of 2 leaks appearing close together, I don't think this is the Note 4.
Samsung's phablets have super sharp screens, while the SM-2558 has a fairly ordinary 7" screen, and that's not the only difference. The Note 3, for example, has 3GB RAM, a 13MP camera, and a stylus. It also has a faster CPU.
I really don't think the SM-2558 is good enough to belong to the Galaxy Note line. In fact, if not for the few differences between this phablet and the Tab 4 7.0, I would have thought this was the 3G or 4G equipped version of that budget tablet (there's one mentioned in the official specs). But the screen resolution, cameras, and weight shot that idea down.
So at this point we're just going to have to wait and see if this phablet shows up anywhere.