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 the Regulatory Compliance and Safety Information that shipped with your hardware 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 Read the installation instructions before you connect the system to its power source. To see translations of the warnings that appear in this publication, refer to the Regulatory Compliance and Safety Information document that accompanied this device.

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 document that accompanied this device.

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 document that accompanied this device.

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 that 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 removing 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.

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 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 cable modem termination system (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 32 to104ºF (0 to 40ºC), 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 installation and testing of an uninterruptible power source (UPS) with sufficient "in-rush" starting current capability to protect against power failures and power anomalies such as spikes and brown-outs at your site. A Cisco 6920 AC-input power supply has an electrical current rating of 4A, but initial starting current is higher. Size the uninterruptible power source accordingly. 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 convection 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	32ºF (0ºC)	104ºF (40ºC)
Temperature, ambient nonoperating and storage	-4ºF (-20ºC)	149ºF (65ºC)
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 blank power supply or card slot 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 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:

Shielded 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 Table 2-2 for pin assignments.)

Table 2-2: Ethernet Crossover Cable Pin Assignments

Signal	Pin	Pin	Signal
Transmit Data (TxD+)	1	3	Receive Data (RxD+)
Transmit Data (TxD-)	2	6	Receive Data (RxD-)
Receive Data (RxD+)	3	1	Transmit Data (TxD+)
-	4	4	-
-	5	5	-
Receive Data (RxD-)	6	2	Transmit Data (TxD-)
-	7	7	-
-	8	8	-

Shielded 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 Table 2-3 for pin assignments.)

Table 2-3: Ethernet Straight-Through Cable Pin Assignments

Signal	Pin	Pin	Signal
Transmit Data (TxD+)	1	1	Transmit Data (TxD+)
Transmit Data (TxD-)	2	2	Transmit Data (TxD-)
Receive Data (RxD+)	3	3	Receive Data (RxD+)
-	4	4	-
-	5	5	-
Receive Data (RxD-)	6	6	Receive Data (RxD-)
-	7	7	-
-	8	8	-

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.

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 1 RU (1.75 inches or 4.45 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 and connector compatibility as described in the following sections.

DHEI Cables

Distance Limitations and Interface Specifications

DHEI cables should not be longer than 80 inches (2 meters).

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

Recommended Cable (DHEI Simplex)

Belden type 8138 low capacitance computer cable:

Cable outside diameter: 0.330 in.
Overall foil/braid shield
8 twist pairs, each 28 Gage @ 65 ohm/M
Nominal capacitance: 11 pf between paired conductors
Nominal impedance: 120 ohm

Recommended Connectors

15-position
Panel mount receptacle:

AMP HD-22 Series Vertical: 7493741
Right Angle: 1-748390-9 (requires board mount hardware)

: Both styles require female screwlock kit for cable end connector.

Cable terminating plug:

AMP HDP-22 Series: 748364-1

: Requires 22 DF size 748333-x pins
: Recommend 745171-5 shielded backshell with 747784-4 jackscrews

Figure 2-1 and Figure 2-2 show the signal-to-pin designations for the DHEI input and output connectors.

Figure 2-1: DHEI Input Connector—Signal-to-Pin Designations

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

Cisco Part Numbers

DHEI Input Cable

Cisco part number: cis72-2072-01

DHEI Output Cable

Cisco part number: cis72-2085-01

Cabling Requirements for DVB I/O Cards

Cisco recommends that cables used for connecting the DVB I/O card (output only) should be "Precision Video Cable" cables or an equivalent (such as CommScope E83032 (quad-shielded) or Belden 9167 (triple-shielded) high-quality 75-Ohm coaxial cable constructed using at least 95 percent braid-over-foil shielding. This type of cable is required to ensure meeting Electromagnetic Compatibility emission requirements as well as assuring superior signal integrity.

Connecting the Cisco 6920 to Third-Party Equipment

DHEI Cabling Requirements for Motorola/GI Equipment

Most cable headends use integrated receiver transcoders (IRTs) from General Instrument (now part of Motorola) to receive digital programming from AT&T Headend in the Sky (HITS) and other satellite-based distributors. The IRT, which decrypts and demodulates the quadrature phase shift keying (QPSK) feed, has a DHEI (26-pin connector) output that can be interconnected with the Cisco 6920 DHEI Input or I/O module (15-pin connectors) using the CAB-6920-DHEI-Input cable. A CAB-6920-DHEI-Input cable can also be used to connect the Cisco 6920 DHEI I/O module output (15-pin connector) to the IRT DHEI input (26-pin connector) for reencryption and (quadrature amplitude modulation (QAM) of the newly stat-muxed transport stream for distribution through the cable plant. (See Figure 2-3.)

Figure 2-3:

Motorola/GI has introduced a Modular Processing System (MPS), which can contain modules that decrypt, demodulate, remultiplex, reencrypt, and remodulate digital video streams. An additional DHEI or DVB-ASI module is used to interconnect the MPS to the Cisco 6920. Motorola/GI has also introduced a new DSR 4400 satellite demodulator. Both of these products use 15-pin connectors for DHEI rather than the 26-pin connectors used in the IRTs.

Note Cisco does not provide the interconnect cables between the Cisco 6920 and these products. The appropriate DHEI (15-pin to 15-pin) cables are available from Motorola as an accessory.

Cabling for Scientific-Atlanta Equipment

Many cable headends also use multiple decryption receivers (MDRs) from Scientific-Atlanta to receive digital programming from Time warner's Athena or other satellite-based distributors. The MDR, which decrypts and demodulates the QPSK feed, has a DHEI (26-pin connector) output that can be interconnected with the Cisco 6920 DHEI Input or I/O module (15-pin connectors) using the CAB-6920-DHEI-Output cable.

Note It is the DHEI output cable and not the DHEI input cable (as was the case with the Motorola IRT).

The newly stat-muxed output of the Cisco 6920 can be forwarded to a Scientific-Atlanta encryptor/modulator (for example, the D9476) via DHEI (through the 15-pin DHEI I/O output connection) with CAB-6920-DHEI-Input cable or more commonly via DVB-ASI (through the DVB-IO module). (See Figure 2-4.)

Figure 2-4:

Scientific-Atlanta sells a high-density multiple QAM modulator (MQAM), that supports up to four 6-MHz QAM 256 outputs in a single rack unit. Due to the MQAM's limit of only two DVB-ASI input ports (the MQAM does not support DHEI interfaces), the Cisco 6920 cannot fully utilize the MQAM's bandwidth requirements through the existing DVB I/O card outputs.

Cabling Requirements for Other Headend Equipment Vendors

Other headend equipment manufacturers produce equipment that typically uses only the DVB-ASI protocol. Should you encounter a satellite demodulator, MPEG encoder, or multiplexer that is to be connected to the Cisco 6920 via DHEI, keep in mind that Cisco provides cabling only for the 26-pin-to15-pin conversion. Any 15-pin-to-15-pin cabling must be acquired from the equipment vendor and not from Cisco.

Table of Contents

Recommended Cable (DHEI Simplex)

Recommended Connectors

DHEI Input Cable

DHEI Output Cable