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Q. How does 56Kbps modem technology work? What makes it different from
28.8Kbps and 33.6Kbps technology?

A. The basic concept behind this communications technology is that the
public switched telephone network (PSTN) is increasingly a digital rather
than analog network. Existing analog modems, such as V.34, "see" the PSTN
as an analog system, even though the signals are digitized for
communications throughout most of the network. Rockwell's 56Kbps technology
looks at the PSTN as a digital network which just happens to have an
"impaired" section represented by the copper wire connection between the
central office and the user's home, usually referred to as the analog local
loop. To make the technology work over that analog loop, it must "equalize"
the line using special technology that converts the signal samples seen by
the user's modem into the equivalent of what is being sent from the central
office.

More details are available in our white paper, which is available on our
web site at http://www.nb.rockwell.com/mcd/K56Plus/56k_wp.html.

Q. Is this new 56Kbps analog modem technology an extension of V.34
(28.8/33.6Kbps)?

A. No, the techniques used in V.34 (28.8Kbps) have been exploited to their
limits. This is a new technique where the network is viewed as a digital
transmission medium and the data is encoded for transmission over the
user's telephone line, also known as the analog local loop.

Q. Can any two modems incorporating this technology connect at 56Kbps?

A. Yes, if one is a central-site modem with a digital connection to the
network. On the other hand, two end-user modems incorporating this
technology will not connect using this technique. Furthermore, 56Kbps
speeds can only be achieved on good line conditions.

Q. Does 56Kbps technology have different applications than previous modems,
then?

A. 56Kbps technology will primarily be used for faster web browsing and
Internet access, and for faster remote access to corporate LANs that
digitally connect to the PSTN.

Q. How can you receive data at 56Kbps when the theoretical Shannon's Limit
is about 35 Kbps?

A. Shannon's limit is theoretically determined by the impairments (noise)
in the telephone link. This new technique relies on a reduced noise
environment due to a digital connection to the network by the service
provider and a new encoding technique.

Q. Why hasn't this technology been developed before?

A. Actually, the concept has been around for a number of years but it
hasn't been practical because most modems installed at service providers
used to use analog connections to interface to the network.

Q. Is this new high-speed analog modem technology a compression algorithm
or a modulation scheme?

A. It is neither a compression algorithm nor a modulation scheme. Data is
actually passed on the telephone line at 56Kbps. It is a technique for
encoding data for transmission over the telephone line -- we prefer to
refer to it as an encoding technique instead of a modulation scheme.

Q. What's the difference between modulation and encoding schemes?

A. In modulation, a carrier is modified so that it carries information.
Ordinary modems modulate a carrier to carry digital data. In this new
technique we encode the data. By "encoding," we mean that data is sent in
digital form through the network, and encoded in such a manner that it can
pass through the user's analog telephone link at a high rate. This is a
very technical area which can best be understood by reading our white paper
describing the technology.

Q. Can you define this new product within the context of ISDN, frame relay,
cable modems or ADSL?

A. There are no relationships. In reference to all of these techniques, the
advantage of this new technique is that it works over the existing switched
telephone network. It does not require the telephone company to replace or
add any new equipment.

Q. What do you mean in your news release by "bridge the gap" between
current analog transmission rates and fully digital communication?

A. ISDN, which provides two 64Kbps channels, has not yet achieved a
significant penetration in the home market. This 56Kbps technology will
allow users to gain the speed advantages of almost one ISDN channel without
having to order and pay for a new ISDN telephone line.

Q. How will 56Kbps services compare in price to other digital services?

A. This technology does not require new services. It will utilize the
existing analog telephone service.

Q. Can the 56Kbps technology go to even higher speeds? Under what
circumstances?

A. Theoretically, the technology can approach 64Kbps; however, there are a
number of practical problems with achieving this speed including line
noise, non-linear distortion, the quality of the network codec, and others.
The industry is working to push the technology to its highest possible data
rate, and rates near 64Kbps may be possible in the future.

Q. Does the user need an additional phone line?

A. No, this new technology will work over a single existing analog phone
line.

Q. Does the phone company need to install new equipment?

A. No. The use of this technique will be transparent to existing phone
company equipment.

Q. Does the user need new equipment?

A. The user must have a modem which implements this new technology.

Q. Will it work on long-distance calls or only local calls?

A. It will work on both local and long-distance calls, depending upon the
network interconnection. See our white paper for more details.

Q. What do the ISPs have to do for users to get 56Kbps Internet access and
web-browsing speeds?

A. Similar to end-users, the ISP must have equipment that includes modems
which support this technique. Additionally, the ISP must utilize a digital
connection to the network. This will be an extremely straightforward
process for ISPs who are installing new central-site equipment featuring
the new 56Kbps modems. However, ISPs who wish to upgrade existing
central-site equipment to the new 56Kbps technology face two additional
issues.

First, ISPs will probably wish to use ISDN Primary Rate Interface (PRI)
network connections rather than lower-performance T1 "robbed bit"
interfaces. All other things being equal, users will be able to connect at
a higher rate to an ISP utilizing ISDN PRI than to one utilizing a T1
"robbed bit" signaling. Many ISPs, therefore, will want to upgrade their
network interface to ISDN PRI, as well as adding 56Kbps modem capability to
their central-site equipment.

Second, ISPs will need to make sure that their equipment provides adequate
compression performance at 56Kbps operation. Without adequate compression
performance, the "effective throughput" may not be much better than what
users experienced at 28.8 Kbps or 33.6 Kbps. Some of the central-site
modems which are being promoted as "upgradeable" to a 56Kbps encoding
scheme may only have enough processing power to support adequate
compression performance at 28.8Kbps and 33.6Kbps speeds. In these cases,
users may not experience better throughput than when they were operating at
28.8Kbps or 33.6Kbps speeds. This is an especially insidious problem
because it occurs at the central site, out of the control of the user. Even
if the user has purchased a new 56 Kbps modem, the throughput may be
limited by poor compression performance at the central site.

See [Image] for the complete listing of modem manufacturers and Internet
Service Providers (ISPs) supporting Rockwell K56Plus technology.

Q. What exactly is "effective throughput?" Why is it so important to
achieving full 56Kbps performance?

A. It is important to first understand how modems work. Data is first sent
into a modem, where it is compressed and sent over the telephone line to
another modem, where it is then decompressed. The amount of data that can
be sent into the modem and effectively transmitted to the other end is
called the effective throughput. The level of compression that the modem's
processing power can support affects the effective throughput. The better
the compression, the higher the effective throughput. And the higher the
effective throughput, the faster the Web pages will come up on the user's
screen.

Q. Will 56Kbps technology be backward-compatible with existing modems that
are already installed?

A. Products incorporating this new technology will also contain all
previous modem modulations, including V.34, V.32bis, and facsimile
modulations. During the initial stages of a connection the two modems will
determine what modulation and at what speed the transmission will occur.

Q. Why can't users get 56Kbps speed both sending and receiving?

A. It is more difficult to equalize the upstream channel, and therefore
more difficult to achieve the same high data rates as are achieved in the
downstream channel. However, for Internet access, the data rate in the
upstream direction is less important than downstream, since the upstream
channel transmits mostly "key strokes and mouse clicks." At present, a data
rate of around 30 Kbps can be attained in the upstream direction, but
research continues toward increasing that rate.

Q. Why can't all 56Kbps modems connect to each other, initially? What
happens if a user with one manufacturers' 56Kbps modem tries to connect to
a remote network or ISP that has another manufacturers' 56Kbps modem on the
other end?

A. Although it appears that most companies are using the same basic
technique to achieve 56Kbps operation, the specific design choices are
unlikely to be the same. However, if two modems are unable to connect at
56Kbps, they will drop down to a mutually interoperable industry-standard
data rate like 28.8Kbps or 33.6Kbps. Rockwell is working with the
appropriate standards bodies, toward the development of a ratified
specification that will serve as a worldwide interoperability vehicle.

Q. What is happening with the industry standards effort for 56Kbps modem
technology? What standards organizations will be involved, if any, in
addition to the ITU?

A. The ITU sets international standards and thus would be the preferred
standards body for this technology. On November 13, 1996, Rockwell
Semiconductor Systems hosted the TR-30 Pulse Code Modulation (PCM) ad hoc
group, the first standards meeting aimed at creating draft standards for
PCM modem technology. These draft standards are being developed to ensure
interoperability between 56Kbps products from a broad spectrum of modem
vendors and other communications equipment suppliers. Rockwell was joined
at the meeting by a number of leading U.S. PC and communications companies
including Intel, Lucent, Hayes, Motorola, IBM, Compaq and Cisco. This ad
hoc committee has been created under the direction of the Electronics
Industry Association (EIA) and Telecommunications Industry Association
(TIA) to develop an EIA/TIA interim standard for U.S. 56Kbps PCM modems by
mid-1997. The TIA TR-30 group also will serve as the advisory committee to
the U.S. government on modem-related issues involving the International
Telecommunications Union (ITU). It is expected that the group's interim
work in the U.S. will form the basis for a U.S. submission to the ITU for a
worldwide standard for 56Kbps modem technology. Rockwell is a charter
member of this TIA group and is the assistant editor for the draft
standard, working with Motorola.

Q. Why is interoperability so important to the success and adoption of
56Kbps modem technology? Will 56Kbps modem technology follow the same
standards-development process as the previous 28.8Kbps and 33.6Kbps modem
technology? Are there unique new interoperability issues that need be
resolved before 56Kbps modem technology achieves its full potential, since
this technology relies on the digital telephony infrastructure?

A. Interoperability is critical to any modem technology. In the case of
56Kbps modems, the technology introduces new issues which may require
slightly different handling by the industry standards bodies as compared to
previous 28.8Kbps and 33.6Kbps efforts. Rockwell is working with a number
of other leading PC, modem, and telecommunications equipment vendors to
address these new issues which may impact the future success of 56Kbps
modems. Also, Rockwell has joined with Lucent to announce that the two
companies will make their 56Kbps modem chipsets interoperate at 56 Kbps.
Agreements like this help to ensure that customers who purchase a modem
that implements Rockwell's K56Plus will have the highest probability of
achieving a connection at speeds up to 56Kbps.

Q. Some people say that the first to market will achieve status as the de
facto 56Kbps standard. Why isn't that true? Why does the industry need to
wait for the standards bodies to determine specifications?

A. The diffusion rate for a new modem technology like this will be slow,
and it is critical that the industry develop worldwide standards. Early
installations of 56Kbps will likely be "show POPs" rather than general
deployment. Network operators will likely move slowly to avoid problems for
their users. The issue of "which 56Kbps?" will disappear when there are
standards. Rockwell is an active participant in the standards-development
process, and is also working very closely with the central-site equipment
suppliers who provide the critical ISP technology to make 56Kbps work.

Q. What is the next step after the TIA/TR30 PCM Modem interim
specifications are completed?

A. Once the TIA PCM ad hoc committee develops its interim draft standard,
for which Rockwell is the assistant editor, it will likely be submitted to
the ITU. Modem manufacturers may choose to implement the TR30 interim
standard until the ITU standard is achieved.

Q. How long will that process take?

A. The TIA PCM ad hoc committee has committed to finalizing a draft
standard by mid-1997. The ITU standardization process could take another 12
to 15 months.

Q. When can we see Rockwell's K56Plus?

A. Rockwell will be demonstrating its K56Plus technology at COMDEX.

Q. Why has Rockwell announced K56Plus before it's ready to ship?

A. It takes time to educate people about this new technology, and for
central-site equipment providers to incorporate the technology into their
plans. This is not like traditional modem products that operate in an
isolated environment -- 56Kbps technology is just one component of a large
network infrastructure including both central-site and client-side modems.
Rockwell announced early to help prepare the market for the final product
and for its successful migration into customers' hands.

Q. What will be the price premium of modems incorporating Rockwell's
K56Plus technology over today's high-speed V.34 (33.6Kbps)modems?

A. It is too early to know how modem manufacturers will price their
products. However, it's likely that this new technology will follow the
same price path as 28.8Kbps modems, which entered the market at retail
prices in the mid $200 range, and quickly came down in price to under $100.

Q. What customer support is there for Rockwell's K56Plus technology?

A. Rockwell has already gained public support for its K56Plus technology
from key central-site modem suppliers including Ascend, Cascade, Hayes,
Microcom and Shiva, plus more than 100 leading client-modem manufacturers.
These manufacturers support an installed base of more than 40 million modem
users.

See [Image] for the complete listing of modem manufacturers and Internet
Service Providers (ISPs) supporting Rockwell K56Plus technology.

Q. What modem experience has Rockwell applied to the development of its
K56Plus technology?

A. Rockwell has been a proven modem technology leader, and will continue to
apply that knowledge base to our 56Kbps modems. The company has shipped
more than 25 million high-speed modems for PC-based client subscriber
applications in 1996 alone, and has extended its already well-established
market leadership position of central site modem connection points.
Rockwell also has experience in ATM, frame relay and other technologies
needed to provide complete networking solutions.

Q. What is Rockwell's current worldwide market share for modem products?

A. According to market analysis by Dataquest and Rockwell, between January
1995 and March 1996, more than 70 percent of access concentrator ports,
which contain a central-site modem, were based on Rockwell modem chipsets.
Rockwell also supplies more than 50 percent of the worldwide modem products
into remote modem applications.

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