The following images show the back panel
of the PA-820 and PA-850 Series firewall and the table describes
each back panel component. The only difference between the back
panels of the two firewalls is that the PA-820 has one fixed power
supply and the PA-850 firewall has two hot-swappable power supplies
(the second power supply is for redundancy).
Use the power supply input(s) to connect
power to the firewall.
PA-820 firewall—Single fixed
AC power supply and power input.
PA-850 firewall—Two AC power supplies and power inputs.
Use the single post ground stud to connect
the firewall to earth ground (ground cable not included).
Fans that provide ventilation and cooling
for the firewall.