SOME QUESTIONS AND SUGGESTIONS:
AF610 WEATHER RECEIVER: There may be a need to remote the Alarm TEST/RESET switch over some distance to a console or other panel. See FAQ Link AF610/Q1
FM Receivers: There may be a need to set the receiver frequency of operation in 50 KHz steps. See FAQ Linl FM REC/Q1
FM Receivers: There may be a need to operate the FM Stereo receiver in the Mono mode of operation. See FAQ Link FM REC/Q2
Everything you wanted to know about SCA operation: (FCC Subcarrier Information)