Relative to NHPD and "E" The Motorola Sabers of ages past had "E" capability. This became evident when the bridge connecting Connecticut Chapel Street South and Sargeant Drive was installed, the NHPD CITYWIDE coms were "E". I asked around with some of the "Brass" and was told "Yeah, we can turn it on and off on our portables" BOOM! Present day, it's not known whether all of the "P" units have "E" capability....but
the primary detective channel (it's not 460.100) is both P25 and "E" full time. Yes, you will hear "I" units come onto the two patrol channels in the clear . That is so when there is a need to coordinate with a marked patrol unit. As far as IS 5 in concerned on 460.100, that is in service sporadically as conditions/volume/budget dictates.