Mirrored Memory Module Note: For full instructions on installing the M3, see its Installation Guide (ESI #0450-0912). The Mirrored Memory Module (M3) ensures reliability and survivability of compatible ESI Communications Servers. Using RAID1-1 hard-disk drive technology, mirrored hard drives are intended to maintain system operation on one disk drive in the event a hard drive fails. No system programming is required for the M3 to function. Note: The ESI-1000 has all M3 components built-in, so the installation on the ESI-1000 of the hard-drive Memory Modules (see “Procedure for two hard-drive Memory Modules (ESI-1000),” page F.5) enables M3 operation on that system. M3 components are optional for the ESI-600 and ESI-200, and must be installed onto the ESI Communications Server main board. The M3 is a printed circuit assembly that supports two identically configured hard drives, mounted on standoffs. It also has LED indicators, an audible alarm, alarm reset button, and an IDE cable connector for connection to the main board. For the mirroring operation to function properly on the ESI Communications Server, each hard drive must be formatted and prepared by ESI. Installing the M3 (ESI-600 • ESI-200) The M3 kit consists of an M3 printed circuit board, hard drive mounting plate, faceplate, four (4) 1-inch standoffs, 12 nylon spacers (washers), eight (8) screws, and an IDE cable for connection to the main board. Refer to Fig. M3-1, below, to identify and locate where these components will be installed. Memory Modules (hard drives, or HDDs) are obtained separately. Note that each hard drive must be an ESI-formatted drive for the mirroring operation to function properly.