Cabletron Systems 9C300-1 MMAC Plus Environmental Module

The Cabletron Systems 9C300-1 MMAC Plus Environmental Module provides integrated system cooling, environmental monitoring, and out‑of‑band management for the MMAC‑Plus chassis. Mounted in the front of the MMAC‑Plus chassis in the slot above the module card cage, it houses four high‑air‑flow fans whose operation and speed are continuously monitored, with a single fan failure not disrupting system operation. It includes LANVIEW LEDs for at‑a‑glance diagnostics and a front‑panel LCD that shows the Cabletron name and status indicators (STATUS and ALARM) during operation, and it provides a UPS interface for power‑related monitoring. The module monitors external ambient temperature, fan speed, system humidity, and voltages—including the 48 V DC and 3.3 V lines feeding the INB terminator modules—as well as internal operating temperature, all viewable on the Environmental Module Environment Screen. The screen presents voltage readings, Fahrenheit/Celsius temperature, a temperature qualification (COLD, COOL, NORM, WARM, HOT), and non‑condensing humidity levels, while the MMAC‑Plus power supply provides these voltages as input to the Environmental Module.