I've heard digital signals (though not sure it is the standard you
mentioned) on 5703kHz. I used USB. From the FLIP, 15091kHz should have
similar traffic. The frequencies are listed as Raymond 27 (Mountain
Home), though I've heard them in use in the Nellis ranges.

They are listed in the FLIP document ap1b.pdf

wrote:
Hi,

Does anyone know of US frequencies where the MIL-STD-188-110B 39-Tone
Parallel Modem can be regularly heard?

Thanks,
John