in junction boxes for coupling t . v . signals and low frequency power waves on a coax line to a plurality of users , the t . v . signals are coupled via connections in a first compartment to a plurality of coax cables , and the low frequency power wave are coupled via low pass - filters to idc connections in a second compartment . leads from users are passed through a chamber on the wall of the second compartment containing a self - healing , self - supporting insulating substance and attached to the idc connectors . the idc connectors permit the lead to be paired through them so that an installer can know when the leads are properly partitioned .