Instrumentation cables are designed to transmit analog or digital signals to and from measurement, monitoring, or control equipment. Engineered to minimize noise, interference and signal loss for accurate transmissions, instrumentation cables are always shielded, with conductors grouped in pairs or triads.
Shields may be overall, encasing all conductors, or I/O which stands for individual and overall shields. Further, I/O shields might be SPOS (shielded pair and overall shield) or STOS (shielded triad and overall shield).
Cables designated "TC" are 600V Tray Cables, while "PLTC" cables are Power Limited Tray Cables, rated to 300V.