Detection of enemy submarines, and communicating with our own, has continued to be an important area of conventional research for the Navy, so it is no surprise that researching the use of ESP for these purposes would be of interest. Communicating with a submerged submarine is the only kind of communications where the very act of receiving puts the receiver in danger, since submarines must normally stick an antenna out of the water for high speed radio traffic, or rely on trailing a long wire antenna under water relatively near the surface to receive very slow speed traffic using ELF radio waves. Newer techniques may involve the use of blue-green wavelength lasers, but evidently penetration to any depth is still a problem. I suggest that there is already a way of transmitting information using two symbols only, namely Morse Code. Current ELF or VLF radio transmission methods for communicating with fleet ballistic missle submarines to issue them their launch orders involve very low data transfer rates, on the order of 3 to 30 bits per minute, if I am not mistaken.
Messages are very short, consisting of pre-formulated action or targeting codes.
I suggest that telepathic 'Zener Morse' is an operational technique for information transfer under severe signal to noise conditions. In fact the use of five Zener symbols would increase data transfer rates, but at the expense of a higher error rate due to the problems in discriminating between five and just two symbols.