As far as subs go sound powered phones and general speaker systems (1mc, 2mc, 4mc) were still the norm when in operation areas, email was on a laptop that was pretty much bolted into its brackets so on angles and dangles it wouldnt come out, but they were talking about a system that read your tags on the danger tags with a barcode reader (6 years ago) but I'm not sure how far that got.
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ELF is not portable by any stretch of the imagination but I'm guessing that your looking for only portable media / devices which can be used for person to person or some type of voip (voice over internet), as far as subs go I'm not sure that any upgrades have occured which can be used underway (would have to install some type of trasnmitter / reciever inside the hull which could possiably be detected outside the hull. We did have some walkie talkie like devices that were huge and very archaic but face to face was still the prefered method of comunication.
Navy develops two-way radio communication for submerged submarines (3/5/08) -- GovExec.com
Interesting piece that a google search showed up, this will make it so we no longer had to float at periscope depth bouncing back and forth with the waves. It appears that subs coms to shore have started recieveing upgrades but personnal coms are still limited at this time, maybe surface targets err ships will have a better device thats closer to what your looking for.