Rack-Mounting Considerations
Cisco AS5800 Universal Access Server Hardware Installation Guide2-16
Preventing Electrostatic Discharge Damage
Electrostatic discharge (ESD) damage, which occurs when electronic cards or components are
improperly handled, can result in complete or intermittent system failures. The access server
components include printed circuit boards that are fixed in metal ca rriers. These metal carriers
provide electromagnetic interference (EMI) shielding, connectors , ej ec tor levers, or handles to
protect against ESD. Although each carrier is designed to protect the boards, an antistatic strap
should be used. Remember to handle the carriers by the ejector levers, handles, and carrier edges
only; never touch the circuitry or connector pins.
Caution Always tighten the panel fasteners on the Cisco5814 dial shelf cards and dial shelf
controller cards and the captive s crews o n the Cisco7206 router shelf network processing engine and
I/O controller. These screws pr ev en t accident al re mov al, p rov ide pr oper sys tem groun ding , and he lp
ensure that the bus connectors are properly seated.
The following are guidelines for preventing ESD damage:
•Always use an ESD wrist strap or ankle strap and ensure that it makes good skin contact.
•Verify that the equipment end of you r ESD stra p is atta ched to an unf inishe d chassis surface wh en
handling a dial shelf card, module, or port adapter; do not touch the printed circuit board, and
avoid contact between the printed circuit board and your clothing. When working with a dial
shelf card, module, or port adapter, always place it “component side up” on an antistatic surface
or in a static shielding bag. If returning an item to the factory, immediately place it in a static
shielding bag.
•Ensure that all dial shelf cards and dial shelf controller cards with in the Cisco5814 dial shelf and
the I/O controller and network processing engine within the Cisco7206 router shelf are fully
inserted in their resp ective chassis slots. Ensur e that all ejector levers are in their locked position s
and that all captive screws are prop e r ly tig h t en e d. T he cap t ive in st al lation screws prevent
accidental removal, provide proper grounding for the system, and help ensure that the bus
connectors are properly seated.
Caution For safety, periodically check the res istance value of the antistatic s trap. The measurement
should be between 1 and 10 Mohm.
Rack-Mounting Considerations In a typical rack-mount configuration, you mount both the dial shelf and the router shelf toge ther in
a rack, with the dial shelf mounted below the router shelf. We do not recommend that you separate
the dial shelf from the router shelf when configuring the hardware for this system; however , a 20-ft.
interconnect cable is available if you need to install the router shelf in an adjacent rack. If you are
using AC-input power, you mount the AC-input power shelf below the dial shelf.
There is no clearanc e requirement for moun ting the router shelf directly above the dial s helf;
however, if you install anything other tha n a Cisc o7206 router shelf above the dial shelf, follow the
appropriate clearance requirements for the unit you install.
You can stack two access servers in a single rack; ho wev er, you must leave a minimum clearance of
one rack unit between the two systems.
You must install the AC-input power shelf one rack unit, 1.75 in. (4.28 cm) below the dial shelf to
accommodate the DC power cables, the monitor cable, the grounding cable, and the require d safety
cover.