Preparing for Installation

Before installing the Cisco 6920, assemble the equipment needed to support your network configuration and subscriber service offering. Ensure that all power and cabling requirements are met based on the equipment to install. Also ensure that environmental conditions are met to maintain proper equipment operation.

Safety Recommendations

The following guidelines will help to ensure your safety and protect the equipment. This list does not cover all potentially hazardous situations, so be alert.

Review the safety warnings listed here and in Appendix B, "Regulatory Compliance and Safety Information" before installing, configuring, or maintaining the Cisco 6920.
The installation of your Cisco 6920 should be in compliance with national and local electrical codes: in the United States, National Fire Protection Association (NFPA) 70, United States National Electrical Code; in Canada, Canadian Electrical Code, part I, CC22.1; in other countries, International Electrotechnical Commission (IEC) 364, part 1 through part 7.
Never attempt to lift an object that might be too heavy for you to lift by yourself.
Always unplug the power cable before installing or removing a chassis.
Keep the chassis area clear and dust free during and after installation.
Keep tools and chassis components away from walk areas.
Do not wear loose clothing, jewelry (including rings and chains), or other items that could get caught in the chassis.
The Cisco 6920 ships with a 3-wire electrical grounding-type plug, which will only fit into a grounding-type power outlet. This is a safety feature. The equipment grounding should be in accordance with local and national electrical codes.
The Cisco 6920 operates safely when it is used in accordance with its marked electrical ratings and product usage instructions.

Warning Only trained and qualified personnel should be allowed to install, replace, or service this equipment. To see translations of the warnings that appear in this publication, refer to the "Regulatory Compliance and Safety Information" section in this document.

Warning Incorrect connection of this or connected equipment to a general purpose outlet could result in a hazardous situation. To see translations of the warnings that appear in this publication, refer to the "Regulatory Compliance and Safety Information" section in this document.

Warning Ultimate disposal of this product should be handled according to all national laws and regulations. To see translations of the warnings that appear in this publication, refer to the "Regulatory Compliance and Safety Information" section in this document.

Lifting Safely

A fully configured Cisco 6920 weighs approximately 42 pounds. This chassis is not intended to be moved frequently. Before you install the Cisco 6920, ensure that your site is properly prepared so you can avoid having to move a chassis later to accommodate power sources and network connections.

Always disconnect all external cables before lifting or moving the chassis.
Do not attempt to lift the chassis by yourself; have someone assist you.
Ensure that your footing is solid, and balance the weight of the object between your feet.
Lift the chassis slowly; never move suddenly or twist your body as you lift.
Keep your back straight and lift with your legs, not your back. If you must bend down to lift the chassis, bend at the knees, not at the waist, to reduce the strain on your lower back muscles.
Lift the chassis from the bottom; grasp the underside of the chassis exterior with both hands.

Safety with Electricity

The PowerPC cards, I/O cards, input cards, and power supplies are not designed to be removed and replaced while the system is operating.

Caution You must power down the system before moving or replacing any card in the Cisco 6920.

Follow these basic guidelines when working with any electrical equipment:

Before beginning any procedures requiring access to the chassis interior, locate the emergency power-off switch for the room in which you are working.
Disconnect all power and external cables before installing or removing a chassis.
Do not work alone if potentially hazardous conditions exist.
Never assume that power has been disconnected from a circuit; always check.
Do not perform any action that creates a potential hazard to people or makes the equipment unsafe.
Never install equipment that appears damaged.
Carefully examine your work area for possible hazards such as moist floors, ungrounded power extension cables, and missing safety grounds.

Warning Do not work on the system or connect or disconnect cables during periods of lightning activity. To see translations of the warnings that appear in this publication, refer to the "Regulatory Compliance and Safety Information" section in this document.

Caution Before opening the chassis, disconnect the video cables to avoid contact with any voltages.

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 PowerPC card, input/output cards, input cards, and DSP cards consist of a printed circuit board that is fixed in a metal carrier. Electromagnetic interference (EMI) shielding, connectors, and a handle are integral components of the carrier. Although the carrier helps protect the boards, use an antistatic strap whenever handling the PowerPC card, input/output cards, input cards, and DSP cards. Handle the carriers by the handles and the carrier edges only; never touch the boards or connector pins.

Caution Always tighten the captive installation screws on the PowerPC card, input/output cards, input cards, and DSP cards. These screws prevent accidental removal, provide proper grounding for the system, and help ensure that the bus connectors are properly seated in the front plane.

Following are guidelines for preventing ESD damage:

Always use an ESD wrist strap or ankle strap and ensure that it makes good skin contact.
When handling a removed PowerPC card, input/output cards, input cards, or DSP card make sure that the equipment end of your ESD strap is attached to an unfinished chassis surface of the Cisco 6920; do not touch the printed circuit board, and avoid contact between the printed circuit board and your clothing. Always place PowerPC card, input/output cards, input cards or DSP card component side up on an antistatic surface or in a static shielding bag. If you are returning the item to the factory, immediately place it in a static shielding bag.
Ensure that each PowerPC, input/output, input, and DSP card is fully inserted in its chassis slot and that the captive installation screws are tightened.

Caution For safety, periodically check the resistance value of the antistatic strap. The measurement should be from 1 through 10 megohm (Mohm).

Site Preparation Checklist

General Tasks

Review safety recommendations and guidelines.
Complete required general CMTS preparations.
Verify site power voltages.
Verify site environmental specifications.
Create downstream and upstream channel plans.
Sweep, balance, and certify the cable plant per NCTA recommendations.
Make available all required passwords, IP addresses, and device names.
Make available all required tools and cables.
Install and configure the network access server.

Site Requirements

To ensure normal operation and avoid unnecessary maintenance, plan your site configuration and prepare your site before installation. Take into account the following criteria:

Verify that your video inputs are functioning properly. Select channels from the range specified in your channel plan.
Make sure that the site maintains an ambient temperature of 32º F through 104º F (0º C through 40º C), and keep the area around the chassis as free from dust as is practical.

AC Power

The AC-input power supply uses a power factor corrector that allows the Cisco 6920 to operate on input voltage and frequency within the ranges of 100 through 240 VAC and 50/60 Hz.

Note Cisco recommends an uninterruptible power source (UPS) to protect against power failures and power anomalies such as spikes and brown-outs at your site. The AC-input power supply has an electrical current rating of 7A. The UPS rating should accommodate startup in-rush currents in the event that the unit is power cycled; therefore, a 1500-watt plus rating is advisable per fully loaded Cisco 6920 chassis. The UPS also provides power buffering in the case of mains to generated power transfer.

Site Environment

Table 2-1 lists the operating and nonoperating environmental site requirements. Within the specified ranges, the Cisco 6920 will continue to operate; however, a measurement approaching the minimum or maximum indicates a potential problem. You can maintain normal operation by anticipating and correcting environmental anomalies before they approach a maximum operating range.

The Cisco 6920 is cooled by passive conduction from the bottom through the top of the chassis. Keep the top and bottom of the chassis clear of obstructions and away from the exhaust of other equipment.

Table 2-1: Specifications for Operating and Nonoperating Environments

Specification	Minimum	Maximum
Temperature, ambient operating	32º F (0º C)	104º F (40º C)
Temperature, ambient nonoperating and storage	-4º F (-20º C)	149º F (65º C)
Humidity, ambient (noncondensing) operating	10%	90%
Humidity, ambient (noncondensing) nonoperating and storage	5%	95%
Altitude, operating and nonoperating	Sea level	10,000 ft (3,050 m)

Maintaining Normal Operation

Planning a proper location for the Cisco 6920 and the layout of your equipment rack or wiring closet are essential for successful system operation. Equipment placed too close together or inadequately ventilated can cause systems to overheat. In addition, chassis panels made inaccessible by poor equipment placement can make system maintenance difficult. Following are precautions that can help avoid problems during installation and ongoing operation.

General Precautions

Follow these general precautions when planning your equipment locations and connections:

Cisco recommends keeping the Cisco 6920 off the floor and out of any area that tends to collect dust, excessive condensation, or water.
Follow ESD prevention procedures to avoid damage to equipment. Damage from static discharge can cause immediate or intermittent equipment failure.
Ensure that the network processing engine, I/O cards, input cards, DSP cards, PowerPC cards, power supplies, and any power supply or card slot blank filler plates are in place and secure. Cisco recommends that blank filler plates be installed on all unused slots of the chassis to protect against dust and damage, as well as to allow for the proper flow of conducted ventilating air important to the cooling of the Cisco 6920.

Power Considerations

Follow these precautions and recommendations when planning power connections to the Cisco 6920:

Check the power at your site before installation and periodically after installation to ensure that you are receiving clean power. Install a new power conditioner or UPS, if necessary.
Install proper grounding to avoid damage from lightning and power surges.

Tools for Installation

The Cisco 6920 chassis is fully assembled at the factory; no assembly is required. However, you will need the following tools and equipment to install the chassis:

Number 2 Phillips screwdriver
3/16-inch flat-blade screwdriver
Tape measure (optional)
Level (optional)

In addition, you might need the following:

Ethernet crossover cable with RJ-45 connectors—If you plan to connect a computer directly to an Ethernet port on the PowerPC installed in the Cisco 6920, you need this type of cable.
(See Figure 2-1.)

Figure 2-1: Ethernet Crossover Cable and Pin Assignments

Ethernet straight-through cable with RJ-45 connectors—If you plan to connect the Cisco 6920 to an Ethernet hub or switch, you need this type of cable. (See Figure 2-2.)

Note A 12-foot triple shielded Ethernet straight-through cable is included in the Cisco 6920 accessory box. This cable must be used for FCC compliance.

Figure 2-2: Ethernet Straight-Through Cable and Pin Assignments

Equipment Racks

The rack-mounting brackets on the Cisco 6920 are suitable for most 19-inch equipment racks. Before using a particular rack, check for obstructions (such as a power strip) that could impair rack-mount installation. If a power strip does impair a rear rack-mount installation, remove the power strip before installing the chassis in the rack, then replace it after the chassis is installed. Note that you cannot mount the Cisco 6920 on an equipment shelf because the bottom and top of the chassis must be free from obstructions so that air can circulate through the unit.

Allow sufficient clearance around the rack for maintenance. If the rack is mobile, you can push it back near a wall or cabinet for normal operation and pull it out for maintenance (installing or moving cards, connecting cables, or replacing or upgrading components).
Maintain a minimum unobstructed clearance of 2 RU (3.5 inches or 8.85 cm) on the top and bottom of the chassis for the cooling air inlet and exhaust ports. Avoid placing the Cisco 6920 in an overly congested rack or too close to another equipment rack. Heated exhaust air from other equipment can enter the inlet air vents and cause an overtemperature condition.
Always install heavier equipment in the lower half of a rack to maintain a low center of gravity and prevent the rack from falling.
Consider the equipment and cabling that is already installed in the rack. Ensure that cables from other equipment do not impair access to the cards, or require you to disconnect cables unnecessarily to perform equipment maintenance or upgrades.

In addition to the preceding guidelines, review the precautions for avoiding overtemperature conditions in the "Site Requirements" section. To properly install the Cisco 6920 chassis in a rack, refer to the instructions in the "General Installation" section on page 3-3.

Caution To prevent the chassis from overheating, never install the Cisco 6920 in an enclosed rack or room that is not maintained within ambient operating temperatures by proper room ventilation or air conditioning. The unit will overheat if the conducted input air temperature reaches 105º F (41º C).

Cabling Guidelines

This section describes considerations for setting up the cabling at your site. When planning the location of the new system, consider the distance limitations for signaling, EMI, and connector compatibility, as described in the following sections.

Interference Considerations

When wires are run for any significant distance in an electromagnetic field, interference can occur between the field and the signals on the wires. This fact has two implications for the construction of headend wiring:

Bad wiring practice can result in radio interference emanating from the wiring, ingress noise, co-channel interference, and degraded or erratic performance of the Cisco 6920.
Strong EMI, especially when caused by lightning or radio transmitters, can destroy the signal drivers and receivers in the Cisco 6920, and can even create an electrical hazard by conducting power surges through lines and into equipment. (Review the safety warnings in the "Safety with Electricity" section.)

If you use twisted-pair cable in your headend wiring with a good distribution of grounding conductors, the wiring is unlikely to emit radio interference. If you exceed the recommended distances, use a high-quality twisted-pair cable with one ground conductor for each data signal when applicable.

If wires exceed recommended distances, or if wires pass between buildings, give special consideration to the effect of a lightning strike in your vicinity. The electromagnetic pulse caused by lightning or other high-energy phenomena can easily couple enough energy into unshielded conductors to destroy electronic devices. If you have had EMI problems in the past, you might want to consult experts in electrical surge suppression and shielding.

Distance Limitations and Interface Specifications

DHEI cables should not be longer than 10 feet.

Note Cisco recommends that you do not exceed specified transmission rate and distance limits.

Figure 2-3 and Figure 2-4 show the signal-to-pin designations for the DHEI input and output connectors.

Figure 2-3: DHEI Input Connector—Signal-to-Pin Designations

Figure 2-4: DHEI Output Connector—Signal-to-Pin Designations

Table of Contents

Preparing for Installation