Maybe they are communicating, but their signals and means of communication are so alien that we're literally like ghosts in the night.
Pentium 1 @ 133mhz, AT Motherboard, 48 edo RAM, ATI Mach 64 GX 2mb PCI Graphics card, Seagate 402mb HDD, 20x CD Rom, Dataflex ISA Modem (28.8Kps), Windows 95 C