Cisco 6900 Series Multiplexers

Cisco 6920 RateMUX Advanced MPEG-2 Multiplexer

Data Sheet

Cisco 6920 RateMUX
Advanced MPEG-2 Multiplexer

Future-proofing the cable headend with advanced digital video capabilities

The Cisco 6920 RateMUX® is an advanced Moving Pictures Experts Group (MPEG) multiplexing device that assists cable operators in creating customized digital program lineups, while maximizing the quantity and quality of programming in their digital tier. The product extends the life of existing cable plant and set-top equipment by providing a smooth migration path to new digital services such as "enhanced" television and HDTV (which the Federal Communications Commission has mandated as "must carry"). The Cisco 6920 RateMUX aggregates or multiplexes the digital program streams from satellite receivers and local encoders and produces standard MPEG-2 transports which are exported to conditional access (CA)/quadrature amplitude modulation (QAM) devices for distribution through the cable RF plant.

The Cisco 6920 RateMUX accepts discrete MPEG-2 input through interfaces compliant with Digital Headend Interface (DHEI) or Digital Video Broadcasting-Asynchronous Serial Interface (DVB-ASI) standards. It then uses a powerful digital signal processor (DSP) engine to produce MPEG compliant transport streams which have been optimized (statistically multiplexed) through the use of intelligent buffer management and selective bit rate reduction during bit rate peaks.

Figure 1: Cisco 6920 RateMUX


The Cisco 6920 RateMUX supports a number of applications, including:

  • Grooming of digital program lineups—Operators are able to customize local channel lineups from a variety of sources in order to align their services with the preferences of their subscriber base

  • Enhanced television—electronic program guides and other "interactive" data can be multiplexed into the MPEG transport for use by the set-top box (STB)

  • HDTV service—The Cisco 6920 RateMUX can multiplex in HDTV with statistically multiplexed SDTV programs in order to maximize the HDTV's output transport

  • Ad insertion in the digital tier—Local insertion of digital advertising, station promos, or other digital programming into a source program stream through Digital Program Insertion (DPI) support in the Cisco 6920 RateMUX

Chassis and Cards

The Cisco 6920 RateMUX offers a modular and flexible design in a rack mountable 4 RU chassis. The chassis uses a high-speed backplane to interconnect up to eight input/output and function cards.

PowerPC Card

The Cisco 6920 RateMUX PowerPC card controls basic operations such as program prioritization and DSP allocation. The card has a 10BaseT Ethernet port for remote management either via a standard browser that runs resident software for configuring and monitoring the Cisco 6920 RateMUX Multiplexer, or an SNMP agent.

DVB-ASI/DHEI Interface Cards

The Cisco 6920 RateMUX Multiplexer accepts up to 15 discrete MPEG2 transport input streams over interfaces compliant with DHEI or DVB-ASI protocols. It can also generate up to four discrete DHEI or DVB-ASI multiplexed MPEG-2 transports, each carrying enough bandwidth to support either a 64 or 256 QAM device. The interface cards also perform statistical multiplexing and traditional functions such as Packet Identifier (PID) filtering and program clock reference (PCR) jitter removal.

DSP Cards

The Cisco 6920 RateMUX uses programmable DSP cards to perform bit-rate reduction and digital splicing functions. The Cisco 6920 RateMUX engine uses an advanced statistical model to process and recombine video streams for highly efficient, multiplexed retransmission. The software-based DSP architecture supports application flexibility and an easy upgrade path for future enhancements to the Cisco 6920 RateMUX Multiplexer.

The current DSP card contains three DSPs. A six DSP version of the card with faster clocking will be available in early 2002.

Table 1: Cisco 6920 RateMUX Features and Benefits Summary
Feature Benefit

Transport grooming

Customize digital program lineups

Statistical remultiplexing

Optimize output transport bandwidth

Bit-rate reduction

For statistical multiplexing peak rate management

Matching digital ad to source program stream rate

PID filtering and remapping

Accept programming from multiple sources

PCR jitter correction

Ensure smooth display of video on set-top boxes

Preserve selected program quality

Ensure sustained video quality

Set relative picture quality among all channels

Gain flexibility for channel use while protecting high-profile program quality

Settable output rate

Customize output bandwidth to match a specific modulation scheme

DPI Capabilities

MPEG splicing

Support local ad insertion without the expense and effort of decoding, splicing, and re-encoding satellite feeds

DPI API Support

Allows for interoperability with third-party ad servers

Digital cue detection

Enables the time accurate insertion of ads into the digital stream

HDTV Capabilities

Pass-through of HDTV

Meets FCC mandate for carrying off-air HDTV broadcast programs

Remultiplexing data tables from PSIP-generator

Provides support for advanced digital services deployed on PSIP-compliant STBs

Data Capabilities

Remultiplex conditional access and EPG information

Incorporate architecture-specific data in the MPEG transport stream, including data associated with video scrambling

Other Capabilities

Web browser graphical user interface

Easy configuration. Dedicated management PC isn't required

Simple Network Management Protocol (SNMP) support

Standards-based network monitoring

Table 2: Input/Output Specifications
Input/Output Specifications

Digital video format

MPEG-2 main profile at main-level bit rate </=15 Mbps for SD transcoding; MPEG-2 main profile at high-level bit rate </=20 Mbps for HD pass-through

Video resolution, vertical

480, 240 (NTSC), and 576, 288 (PAL)

Video resolution, horizontal

704, 544, 352

Video aspect ratios

4:3 or 16:9

Digital audio formats

Musicam, Dolby AC3

Ethernet Port




Transmission Control Protocol/Internet Protocol (TCP/IP)

Debug/Configuration Port



Input Interface

Number of inputs

Up to 15 per chassis



Information rate

38.8 Mbps for DHEI, 216 Mbps for DVB-ASI

Output Interface

Number of outputs

Up to four per chassis



Information rate

38.8 Mbps for DHEI, 76 Mbps for DVB-ASI

Table 3: Technical Specifications
  • 7 in. (17.8 cm) height 4RU

  19 in. (48.3 cm) width
  19 in. (48.3 cm) depth
  • Fully configured chassis weight is 40 lb (18.4 kg)


100 to 240 VAC, 50/60 Hz, 7A 55W fully loaded


32° F (0° C) to 104° F (40° C)

Compliance, emissions, and certifications

Complies with the requirements of 89/336/EEC EMC Directive

EN55022: 1994+A1+A2 (Class A)

EN50082-1: 1992

United States—47 CFR Part 15 October 1997

Australia/New Zealand—AS/NZS 3548: 1995


Complies with the requirements of 73/23/EEC; Low Voltage Directive; EN60950:1992+A1+A2+A3+A4+A11

Service and Support

Service and support for the Cisco 6920 RateMUX are available on a one-time or annual contract basis. Support ranges from help-desk assistance to proactive, on-site consultation. All support contracts include software updates, full access rights to, and 24-hour technical assistance. Contact your local Cisco sales office for more information.

Ordering Information

The Cisco 6920 RateMUX is available in a variety of configurations, based on interface cards, DSP cards, and software versions chosen. The specific product codes and descriptions are detailed in Table 4.

Table 4: Cisco 6920 RateMUX Product Codes and Descriptions
Product Number Description
6920 RateMUX

Chassis, Power Supply, Power PC card

Software Options—Standard or DPI version


DSP card with 3 DSPs

6920-DSP6 (orderable early 2002)

DSP card with 6 DSPs


DVB input/output card (3 in, 2 out) (output is cloned)

6920-DVB-I/O2 (orderable early 2002)

DVB input/output card (3 in, 2 out) (dual output DVB)


DVB input card (4 in)


DHEI input/output card (3 in, 1 out)


DHEI input card (4 in)


DHEI input cables (GI Compatible)


DHEI output cables (SA compatible)

For More Information

For more information about the Cisco 6920 RateMUX, visit