I just completed installing a system in our firehouse. Cost us roughly $1300 for all the parts and I did all the labor. Its not really difficult. We have our high band and low band base radios as Aux inputs and the fire station alerting system voc going into the telephone line in connection. Basically when the VOC "opens up" it silences all the other radios if they are putting over any audio and only the VOC system can be heard. I installed 3 new metal box speakers around the firehouse in the offices and dayroom. In the bays I put 2 bull horn type speakers. If you want more information I would be glad to help. You could easily wire up the out put of the pager amplified charger as an input instead of what we have done.
-Russo