The RS-140 is a switch panel designed for use with the N-8000RS or N-8010RS 2-Core Shielded Substation Interface Unit. It is equipped with a Call button and a Privacy button, and can be installed in a 1-gang electrical box. By connecting a high impedance speaker to it, hands-free conversation with the master station can be made through its speaker. Also, it can be used in connection with the RS-141 Ip Intercom Option Handset.