All installed power supplies must blow air in the same direction and must match the airflow direction of the installed fan modules.
A power supply with a red tab provides front-to-back airflow for power supply cooling. All 5520 Series switches are available with front-to-back airflow.
A power supply with a blue tab provides back-to-front airflow for power supply cooling. 5520-24T-BASE, 5520-24T-ACDC, 5520-24X-BASE, 5520-24X-ACDC, 5520-48T-BASE, 5520-48T-ACDC, 5520-48SE-BASE, and 5520-48SE-ACDC switches are available with back-to-front or front-to-back airflow.
