The CSI (Repeater Tone Panel) Company in Lynnwood, WA is long out of business. CSI was a manufacture of Commercial Two-way Radio CTCSS - Digital sub tone panels. They are often a dark gray-blue colored unit with a front panel red LED display and small numbered keypad. At least two or three models were made; one a remote controlled unit supplied without the front panel keypad, another late production unit with telephone interconnect. Connections were made to the repeater via a real panel D-9 or D-15 (depending on the model) jack/plug assembly.