General theme- no electronics until A-week, and then it will vary by company. Cell rules relaxed lately since they did away with the landlines in the rooms.
Cell- ATT, Verizon, and Sprint all work more or less in the main areas. And will all three have holes in certain barracks/spots.
Bring yours to R-day in something that will survive storage, as you'll want it after marchback when allowed. Can't have it during CBT, but very handy after, especially during reorgy.
The coverage situation has improved somewhat this year, but it's still common to have to find the magic spot in your room, etc. Some barracks have repeaters from the different vendors, but it can vary by floor, even room. Thick granite walls and UHF radio waves do not play well together!
Beyond that it does not matter much even in the Academic year, as plebes can't use cells until you get into areas where plebe restrictions do not apply. (More or less away from the Barracks, plain, academic area, messhall, etc)
And the grey trousers do not have pockets that carry them well, so most cadets we know/knew did not bother carrying them as plebes except for weekends & trip sections.
Head much off post and it's very spotty, but that largely won't be an issue till CFT at Buckner. But even there most cadets can find coverage spots.
Personal laptops- Not advised or needed. Many threads on this.
Ipads/tablets- Company policy varies, but some have them, and the never ending rumors about using for textbooks are very strong this year.
Todate, No wireless in barracks / main campus, so tables are not very useful unless you have one with a mobile data plan. Or a phone with a hotspot.
Smartphones seem to be the norm, and seems to make up for not having widespread wireless coverage.
Most appointees worry too much about electronics other than cell phones. Personal laptops, gaming computers, xboxes, etc are really not advised till later years and most get by without them. If you see the situation change while you are there, you can have it shipped. And you'll find someone who has xbox or similar. You'll figure it out.