Correct. Mount Pleasant PD remains on the same frequency but is switched to P25. See the link below.
Subcategory: Municipalities/Mount Pleasant Details (Westchester County)
www.radioreference.com
I haven't heard of the SMS100. Is that like some kind of Text Messaging upgrade? LOL. Anyway, Yes, I have my SDS200 listening to Mount Pleasant PD (And other P25 departments), and it's great.
Also, Pleasantville PD uses LTE, so when they do, you won't hear them. I get them on my SDRs using SDR Trunk, but only when they Affiliate to RF, which is not a lot of the time. They are on the Zone 2 and Zone 3 Simulcast. I think the LTE Network differs from Verizon, but I get like no signal, sometimes not even LTE, in the village around the firehouse and downtown near Manville and Bedford Roads. When I do get LTE, it's very, very slow.
Dobbs Ferry PD also relies on LTE heavily, so im surprised when I hear them.