The fundamental concept of Clear-Com Partyline intercom is that all channels are terminated in one location, preferably at a main station or power supply.
NOTE: There should be one, and ONLY one, termination for each channel in the system.
The concept is to minimize impedence changes on the line when user stations are removed from or added to the line. An un-terminated line will cause excessive levels, possible oscillation of line drivers and squealing in the headsets. An intercom line with double or multiple terminations will cause low levels and the inability to null the headsets.
The termination switches on the main station should be set to the OFF position only if the channel is terminated by another main station or power supply in the system. If there are no other main stations or power supplies terminating the line, the termination switch on each channel of the main station should be switched to ON. All unused intercom lines must also be terminated.