                             
Advanced Digital Network (ADN)
----------------------------


Description
-----------

Advanced Digital Network (ADN) is a digital, private line
transport service that provides full duplex four-wire
transmission of synchronous serial data.  ADN boasts a complete
range of features including variable speeds, customer-controlled
network reconfiguration, and network control and diagnostics. You
can even combine your 1.544 mbps High Capacity Digital service
with ADN service to take advantage of High Capacity Digital
Service (HCDS) economies.

ADN's evolutionary, microprocessor-based technology offers the
most advanced transmission capabilities available today.  This
innovative technology offers new speeds -- 19.2, 32, 38.4, and 64
kbps.  For the first time, variable speeds and new network
control and diagnostics are available to you in a digital format.
Meanwhile, ADN's error control capabilities exceed all existing
standards for error correction performance.  And while it offers
many Integrated Services Digital Network (ISDN) capabilities now,
ADN also allows a smooth transition into your ISDN future.

Flexibility
-----------
If your organization is growing, you are well aware of the need
for control and flexibility of your communications resources.
ADN offers unsurpassed flexibility that helps you meet the
demands on your network more efficiently.  The variable speed
service will help you support multiple applications.  ADN's
reconfiguration lets you adapt your network to meet daily,
occasional, or seasonal data traffic needs; you can reconfigure
your T-1 network or individual channels over dial-up or dedicated
facilities.  Or, if you prefer, a Pacific Bell employee will
reconfigure your network for you when you contact the Customer
Interface Management Site (CIMS).

Disaster Recovery
-----------------
ADN's reconfiguration is the ideal solution for handling a
disaster recovery situation.  If a key element in your network
fails, you can immediately reroute traffic to circumvent the
problem.  And ADN's network control and diagnostics help you
monitor performance, identify and isolate problems, and make
adjustments within the network so that you can obtain optimal use
of your network.

Universal Availability
----------------------
ADN provides intraLATA service and will connect to interLATA
services.

Effective Network Control
-------------------------
If your company is growing, you realize the value of complete
network flexibility, as sell as advanced network control and
diagnostic capability.  With the constant flux in communications,
your business will benefit from communication channels that are
available and can be changed virtually on demand.  With ADN, you
get this and more.

Improved Efficiency
-------------------
Customer network management features make ADN one of the most
efficient networks available today.  You can finally eliminate
the inefficiency of over-trunking to prepare for peak demand
periods.  With ADN's network reconfiguration feature, you can
route your overload voice or data traffic to the underutilized
legs of your network.

You can minimize the impact of a failure in any critical element
in your network.  With ADN's network reconfiguration capability
you can keep your business running smoothly by routing traffic
around the problem component.

Dependability
-------------
All of ADN's components have proven highly dependable throughout
extensive evaluation and testing.  Much of ADN uses Pacific
Bell's reliable network:  the local loop, the T-1 link, the
digital cross connect system, the master controller (for your
network reconfiguration), and the synchronization network.  And
the truly new, intelligent technology in our Serving Wire Centers
have undergone rigorous testing and have proven the extraordinary
reliability expected of a Pacific Bell network product.

Proven Technology
-----------------
The digital cross-connect system used for your ADN network has
acquired a reputation, over many years and several thousands of
hours of service, as a trouble-free system for user-controlled
network management.

Meanwhile, the critical components are located in Pacific Bell
Serving Wire Centers, which ensures that maintenance will be
available around-the-clock by trained personnel to ensure rapid
restoral.

System Security
---------------
Because ADN is provisioned in Pacific Bell Serving Wire Centers,
it offers a degree of security unattainable by customer-premises
equipment.  It offers security features that make it one of the
most safeguarded systems in the Public Network.

If you want control over individual channels of your T-1 network
-- either at a predetermined time or on demand -- you can have it
with ADN's network reconfiguration feature.  You can manage
network addresses, perform loopback tests, activate and
deactivate network devices, set default parameters, and arrange
time-of-day routing -- among other control functions.

Operational Control
-------------------
ADN offers the operational control that you need over your
telecommunications network.  ADN's combination of network
reconfiguration, control, and diagnostics features lets you
customize your level of control.

The multi-level security used with ADN's customer network
reconfiguration will satisfy even the most security-minded
network manager.  Through a mix of network, system, and
application security levels, access is limited to authorized
customers or authorized users within the customer's business.

Single Point of Contact
-----------------------
The Customer Interface Management Site (CIMS) is a central
response center for your ADN service needs.  And not only will
CIMS be there if you need assistance, they will even step in to
reconfigure your network according to your instructions.

Data Service Unit (DSU) or Adaptive Data Service Unit (ADSU)
------------------------------------------------------------
The customer-provided Data Service Unit or Adaptive Data Service
Unit is the only piece of equipment that you need to have in
order to use the ADN service.  for fixed speeds of 2.4, 4.8, 9.6,
19.2 and 56 kbps, you can use your existing Channel Service
Unit/Data Service Unit.

The Adaptive Data Service Unit is a new customer-provided Data
Service Unit that is able to interact with the new capabilities
of ADN; it is currently available from a number of distributors.

Local Loop
----------
The local loop is a four-wire, non-loaded copper pair that
connects your premises to the local Serving Wire Center.

Serving Wire Center (SWC)
-------------------------
Each Serving Wire Center has a time division multiplexer, called
a D4 digital channel bank, that combines 24 digital channel
signals into one digital T-1 carrier signal.

Interoffice Facilities
----------------------
Fast, accurate T-1 carriers on optical fiber or copper connect
the Serving Wire Centers and the digital cross-connect nodes.
Fiber optics will the the first choice facility to connect nodes
and Serving Wire Centers.

Digital Cross-Connect System (DCS) Node
---------------------------------------
A digital cross-connect system node is a Serving Wire Center that
houses a digital cross-connect system through which all traffic
passes.  The digital cross-connect system is a software-
controlled time division switch that interconnects the T-1
systems.  It facilitates network administration, disaster
recovery, and remote single point testing.

Master Controller
-----------------
The master controller is a remote processor that communicates
with each digital cross-connect system node.  It provides the
capability to access and store models or predetermined routing
plans.  The master controller provides security and partitioning
capability to maintain complete network security.

Variable Speeds
---------------
ADN's variable speed capabilities let you change your network's
transmission speed to meet your unique data needs.  You can use
your Adaptive Data Service Unit (ADSU) to change the data rate
for specific applications or to automatically slow your
transmission speed when unacceptable error levels are reached.
The master Adaptive Data Service Unit will change the rate; all
devices will match the rate.

ADN offers variable speed selection in two ranges:

- 1.2 to 38.4 kbps, including 1.2, 2.4, 4.8, 9.6, 19.2, 32 and
  384. kbps.

- 1.2 to 64 kbps, including 1.2, 2.4, 4.8, 9.6, 19.2, 32, 38.4,
  and 64 kbps.

Network Error Correction:

And innovative, new forward error correction technique is
included with the 1.2 to 64 kbps variable speed range.  If an
error occurs, ADN will automatically correct it, making your
transmissions as error-free as possible.  This technique improves
the network error performance by a factor of 10(-5).

Network Control and Diagnostics
-------------------------------
With ADN, you can choose from a host of optional network
features.  You will have as much control over your ADN network as
you need; if you prefer, Pacific Bell will perform the ADN
network control and diagnostics functions for you.  The network
control and diagnostics features allow you or Pacific Bell to
monitor the network performance of your Pacific Bell ADN services
and adjust for conditions in the network or environment.

For example, by assigning addresses to the intelligent elements
in Pacific Bell's ADN Service, you can monitor segments of the
circuit.  You can:

- Check the status, address, and speed of each intelligent unit
- Perform loopback tests to help isolate problems
- Measure error performance
- Activate and deactivate circuit segments on a selective basis

Network Reconfiguration
-----------------------
Reconfiguration off your network is available with ADN's fixed or
variable speed service.  With it, you can adapt your network to
meet changing communications needs.  Or, if you prefer, you can
call in your reconfiguration needs and a Pacific Bell employee
will reconfigure your network for you.  You or Pacific Bell can:

- Change your individual circuit segments or your T-1 network on
  demand
- Establish time-of-day routing, which reroutes traffic at a
  predetermined time
- Circumvent trouble spots if a network component fails.
- Route overload traffic to the underutilized legs of your
network
  during peak hours.

If you plan to manage the network reconfiguration feature, you
will need a standard RS232 terminal so that you can send your
reconfiguration instructions to the master controller.

Secondary/Subchannel Capability
-------------------------------
ADN's fixed or variable speed service offers a lower speed,
derived data channel that operates with your primary data
channel.  You can use this secondary/subchannel for exchanging
test, diagnostic, measurement, and control messages between
remote terminals.  Or you can use as a slow speed, general
purpose data channel to transport information such as air
conditioning, heating, lighting, refrigeration, or smoke and
security alarm information.


                      ADN Applications
                      ----------------

Banking or Finance
------------------
Banks and finance companies demand secure data transfer over high-
speed, private airlines.  Bank teller networks, credit
verification systems, and other mainframe applications require
daily back up to protect customer records.  ADN meets these needs
and provides applications for Automatic Teller Machines, Point of
Sale terminals, and video teleconferencing among branches.

The daily transfer of large amounts of money over the FedWire
packet switching network remains one of the most critical banking
functions.  With the proliferation of bank mergers and
acquisitions, consolidating and transferring data to a
centralized location has taken on a new meaning.  ADN can help
create a single, unified network with flexible connections and
access to Pacific Bell's Public Packet Switching Network.

Meanwhile, the Securities and Exchange Commission requires that
stock brokerage firms and finance companies provide extensive
disaster recovery facilities, including duplicate operations for
both computer processing and telecommunications.  These
facilities may involve an enormous cost.  ADN, however,
incorporates redundancy into a single network instead of
duplicating capability for separate voice and data networks.

Education
---------
In a campus environment, ADN has a multitude of applications:
file transfer, network management, computer-aided design/computer-
aided manufacturing, disaster recovery, time-of-day routing, and
LAN-to-LAN linkages all have a place in the world of education.
ADN's most valued applications are those that help attract top-
notch students and faculty.

Interactive television and teleconferencing, for example, are
being used by many colleges and universities.  This provides a
way to reach satellite campuses, continuing education students,
and local businesses involved in research consortia.  However,
setting up such a network can be both tedious and expensive.
With the flexible connectivity of ADN, linking groups of
students, teachers, and practitioners is easy.

ADN is also ideal for information retrieval -- linking a card
catalog data base to library terminals around campus.  This
dedicated link allows speedy library searches from many locations
and creates a system that is easy to update, maintain, and use.

Retail
------
In the competitive retail environment, customer service
departments need streamlined data communications to ensure
prompt, courteous responses to consumers' needs.  Electronic
funds transfer, Point of Sale terminals, disaster recovery, time-
of-day routing, and LAN-to-LAN communication all play a role in
improving customer service capabilities.

An automated, paperless inventory system is one way that ADN can
bring a retail business up-to-date.  Many retailers will benefit
from a highly efficient inventory system that facilitates
restocking -- with little or no involvement from managers.  By
creating a flexible network between corporate headquarters,
suppliers, retail outlets, and the public, you can keep abreast
of customers' buying patterns, stock only what sells, and reduce
your need for a large inventory.

Manufacturing
-------------
Many manufacturers today have recovered from the harsh economic
realities of past decades.  Yet a deindustrialized economy
continues to force manufacturers toward even greater productivity
and strategic positioning.  ADN can create an advanced
communications system that is flexible enough to accommodate your
innovative environment.

To increase your productivity and reduce paper flow, you may have
established an automated inventory system or a LAN to link
production plants, sales offices, and research groups.  ADN can
provide further efficiency by linking these partial, innovative
solutions into a comprehensive dedicated network.

And you can use ADN for other applications such as transferring
files, managing your network, video teleconferencing, retrieving
data base information, accessing computer-aided design/computer-
aided manufacturing information, recovering from disasters, and
time-of-day routing.

File Transfer
-------------
Businesses small and large need secure data transfer between
computers.  Whether a hospital is receiving laboratory results, a
manufacturer is transmitting inventory or design information, or
a government office is performing daily tasks, businesses depend
upon the ability to transfer files.

With ADN, the complexities of transporting sensitive information
on magnetic tape or diskettes are not a worry.  ADN provides
direct data links for secure, fast, and dependable transmission
on demand or at a set time each day or week.

Electronic Funds Transfer (EFT)
-------------------------------
Today's fierce competitive banking environment calls for
innovative solutions which are often costly to establish and
maintain.  Electronic funds transfer, for example, can help
maximize your Organization's profitability -- but only if
efficient, cost-effective telecommunications services are used to
get you there.  ADN can help you connect your customers so money
can be transferred whenever necessary.  And because ADN is as
secure and error-free as possible, you can be sure that your
transfer will happen as planned.

Automated Teller Machines (ATMs)
--------------------------------
Today's consumers are on the run and demand the conveniences of
Automated Teller Machines.  If your bank or retail business
offers ATMs or Point of Sale (POS) terminals, you know that these
online transactions require a highly reliable, secure, and fast
circuit so that consumers can deposit, withdraw, and transfer
funds around-the-clock.  ADN is a superior transmission medium
for these online applications.

Video Teleconferencing
----------------------
Video teleconferencing is a valuable tool for many organizations.
Educational institutions can telecast lectures or laboratory
experiments to business or satellite college campuses.
Manufacturing plants can use video to cross-train employees.
Police departments use video teleconferences with District
Attorneys' offices when questioning crime witnesses.
Transportation departments can use video for freeway
surveillance.  And teleconferencing saves costly travel and time
for many corporations.

ADN is a perfect medium for limited duration, high band-width
applications such as broadcasting and teleconferencing.  The
network reconfiguration feature lets you establish real-time,
point-to-point, video teleconferences on demand or on a daily or
weekly schedule.

Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM)
------------------------------------------------------------
If you work in a manufacturing or high-tech environment, you are
aware that your communications requirements can increase
dramatically when your company adds complex simulations programs.
Technologies such as 3-D imaging, mechanical or chemical
simulations, and precise variance calculations may require new
links with data bases and computer networks.

ADN can help you provide a dependable system to meet the demands
of the engineering staff.  With ADN, you can ensure that design
engineers will have ready access to the computer-aided
design/computer-aided manufacturing host -- and that you will
receive maximum productivity from your company's computer-aided
design/computer-aided manufacturing system.

Disaster Recovery
-----------------
If your business has critical information stored in a data base
or depends upon daily contact with the data center, you realize
the importance of protecting yourself from power or equipment
failures.

In the event of an emergency -- caused by natural disaster, line
failure, or human error -- you must quickly switch to a backup
processor, restore computing facilities, and retrieve backup
tapes of data base information to guarantee communications among
departments, decision-makers, and the public.

ADN will allow you to prepare for an emergency.  Just transmit
your preplanned network routing models to Pacific Bell's master
controller.  In the event of a disaster, you can simply send the
instruction to execute the mapped plan, and the network will
begin the backup recovery procedures.

And if you experience a line failure in a portion of your
network, you can easily reconfigure your network to route
critical data traffic to an alternate processing center.

LAN-to-LAN Interconnection
--------------------------
In many businesses, departmental computing systems are isolated
islands of computing power.  Advanced Digital Network can link
your departmental systems so that users can access more of the
data resources available to them.  And if your business is
expanding or launching a new service offering, ADN can help you
establish communication links between multiple locations without
compromising efficiency or wasting resources.  As the technology
or your needs change, you can expand or reconfigure your system
for maximum efficiency.

Low Error Rate
--------------
ADN has an error performance objective of 99.5%, which is
comparable to existing digital services.  Withe the sophisticated
error correction techniques offered with the 1.2 to 64 kbps
variable speed option, steps will automatically be taken to
correct any errors that occur -- making your transmissions
surpass the objective of 99.5%.  Its error correction techniques
alone have improved the inherent network error by a power of 10(-
5).

Dependable Network
------------------
The dependable digital cross-connect system that you will be
using is a trouble-free system for managing your network.
Because the critical network components are located in Pacific
Bell's Serving Wire Centers, you are guaranteed that maintenance
will be available 24 hours a day.





ADN is available in a Fixed Speed and a Variable Speed service.
With Variable Speed the user has the option of changing speeds.


Fixed Speeds                Installation     Monthly
------------                ------------     -------
- 2.4 kbps                    $620.00        $50.05
- 4.8 kbps                    $620.00        $50.05
- 9.6 kbps                    $620.00        $50.05
- 19.2 kbps                   $620.00        $50.05
- 56.0 kbps                   $620.00        $50.05

  plus $6/month per airline mile



Variable Speeds             Installation     Monthly
------------                ------------     -------

- 1.2 to 38.4 kbps            $620.00        $66.85
  plus $6/month per airline mile

- 1.2 to 64.0 kbps            $620.00        $75.25
  plus $12/month per airline mile




For More Information
--------------------
For more information on Pacific Bell's Advanced Digital Network,
contact your Pacific Bell account team.

