I'm presuming you are referring to one that has an installed, and working, APCO P25 digital card.Can you use a BC785D to monitor the Mass SP trunking system?
I'm presuming you are referring to one that has an installed, and working, APCO P25 digital card.
For the older Motorola Type II system, that's going to depend on the site you are trying to hear. The 785D cannot be updated for the custom tabled required for some rebanded frequencies. The key is the number in the fourth decimal place. If that is a 5 (five) for all system frequencies, i.e. 856.73750, then the scanner would work. If that digit for any of the frequencies is a 0 (zero), then the scanner will not correctly track that site,
Your location is indicated as in Essex County. For the site in your county:
Ayers Hill Essex 851.20000 851.37500 852.31250 853.47500c 853.63750c
Three of the five frequencies have a zero in that fourth decimal place, so the BC758D would not correctly track the system.
If you are thinking of the newer, Phase I P25 system, Commonwealth Of Massachusetts (Project 25) System Trunking System, Statewide, Massachusetts - Scanner Frequencies, the scanner cannot track that system at all. It cannot process the 9600 baud control channel data stream used on the Phase I system, though it can handle the 3600 baud used on Motorola Type II systems, providing no custom band plan is needed.