SMS cards are early electronic circuit boards that were standardized to handle logic functions, analog circuitry, or cable connections. Rather than acting as processing units themselves, cards like the 375277 functioned as physical latching mechanisms and mechanical indicators, often used in conjunction with lamps on vintage IBM diagnostic, testing, and control panels. Connector looks to be plated gold. These cards were used from the 1950s-1970s. Due to the age of the card and not having the correct machine, this is being sold for parts. A highly collected part from the earliest days of computing. Full number on card edge:FTA 375277 YB 131788 traces side shows: 397599 Best offers considered. I'm in a mood this week of get things cleared out.