If using an M3U-series tester, use CB25X on every expansion module when regularly testing cables longer than 10 feet, when testing cables with a large surface area shield or conductor, or when working in a high static environment to guard your CableEye tester against damage from electrostatic discharge. On each board, 64 transient suppressor diodes especially designed for fast switching divert any overvoltages to ground before damage to CableEye electronics can occur. The CB25X mounts directly to the 64-pin headers in the expansion module. Attach any cable interface you use directly to CB25X. Required for CableEye M3U series models only. Use CB25 (Item 755) on the control module, and CB25X on expansion modules. Set of two boards with ground bypass wire, thumbscrews, and setup instructions.
NOTE: Once installed, do not remove, not even when shipping the system to us for service.