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Claims  |
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Having thus described our invention, what we claim as new and desire to
secure by Letters Patent is set forth in the following claims:
1. Method for conferencing a phone call and information associated with the
phone call to a plurality of participants in a system having a plurality
of phones managed by a digital switch, a plurality of display terminals, a
host processor, and memory means for storing programs and data structures,
the digital switch including memory means for storing programs and a data
structure for uniquely identifying each phone by an extension, control
means for attaching said plurality of phones and communication means for
communicating with the host processor, the host processor having memory
means for storing a communication manager, data structures and
applications programs and communication means for communicating with the
digital switch and the plurality of display terminals, said method
comprising the steps of:
(a) sending the host processor a communication in response to a call
processing event, said communication containing a source phone extension
and a plurality of destination phone extensions;
(b) receiving said communication by the communication manager of the host
processor;
(c) processing said communication and determining an associated application
program and an associated display terminal to link with each of said
plurality of destination phone extensions; and
(d) invoking said associated application program to communicate with said
associated display terminals to display information associated with the
call processing event.
2. Method for conferencing a phone call and information associated with the
phone call to a plurality of participants, as recited in claim 1, wherein
said step of processing said communication and determining an associated
application program and an associated display terminal to link with each
of said plurality of destination phone extensions includes the steps of:
(a) searching said data structures in said host processor for a match of
said source phone extension and a record of said data structure; and
(b) retrieving an application name of said associated application program
from said record of said data structure.
3. Method for conferencing a phone call and information associated with the
phone call to a plurality of participants, as recited in claim 2, wherein
said data structures include a trunk to application program data
structure.
4. Method for conferencing a phone call and information associated with the
phone call to a plurality of participants, as recited in claim 2, wherein
said data structures include a direct network indirect service to
application program data structure.
5. Method for conferencing a phone call and information associated with the
phone call to a plurality of participants as recited in claim 2, including
the steps of:
(a) searching said data structures in said host processor for a match of
said destination phone extension and a record of said data structure; and
(b) retrieving an address of said associated display terminal from said
record of said data structure.
6. Method for conferencing a phone call and information associated with the
phone call to a plurality of participants as recited in claim 1, including
the step of updating the data structures with information associated with
each participant.
7. Method for conferencing a phone call and information associated with the
phone call to a plurality of participants as recited in claim 1, including
the step of executing an application program to initialize the data
structures in the host processor.
8. Method for conferencing a phone call and information associated with the
phone call to a plurality of participants as recited in claim 1, including
the step of dynamically varying the data structures.
9. Method for conferencing a phone call and information associated with the
phone call to a plurality of participants, as recited in claim 1, includes
the step of displaying information on each of said plurality of display
terminals before the participant phone calls are completed.
10. Method for conferencing a phone call and information associated with
the phone call to a plurality of participants, as recited in claim 1,
including the steps of:
(a) accessing the data structures in the host by an application program;
(b) retrieving information from said data structures; and
(c) performing additional processing based on said information.
11. Method for conferencing a phone call and information associated with
the phone call to a plurality of participants, as recited in claim 1,
wherein said step of sending the host processor a communication in
response to a call processing event, said communication containing a
plurality of source phone extensions and a plurality of destination phone
extensions, includes the step of formatting said communication in
accordance with a logical unit six dot two (LU 6.2) transaction.
12. Method for conferencing a phone call and information associated with
the phone call to a plurality of participants, as recited in claim 1,
wherein said phone call originates internally from the digital switch.
13. Method for conferencing a phone call and information associated with
the phone call to a plurality of participants, as recited in claim 1,
wherein said phone call and information are transmitted through the
digital switch.
14. Apparatus for conferencing a phone call and information associated with
the phone call to a plurality of participants in a system having a
plurality of phones managed by a plurality of digital switches
communicating via network means, a plurality of display terminals, a host
processor, and memory means for storing programs and data structures, the
digital switch including memory means for storing programs and a data
structure for uniquely identifying each phone by an extension, control
means for attaching said plurality of phones and communication means for
communicating with the host processor, the host processor having memory
means for storing a communication manager, data structures and
applications programs and communication means for communicating with the
digital switch and the plurality of display terminals, comprising:
(a) means for sending the host processor a communication in response to a
conference call request, said communication containing a source phone
extension and a plurality of destination phone extensions;
(b) means for receiving said communication by the communication manager of
the host processor;
(c) means for processing said communication and determining an associated
application program and an associated display terminal to link with each
of said plurality of destination phone extensions; and
(d) means for invoking said associated application program to communicate
with said associated display terminals to display information associated
with the conference call request.
15. Apparatus for conferencing a phone call and information associated with
the phone call to a plurality of participants, as recited in claim 14
further comprising:
(a) means for searching said data structures in said host processor for a
match of said source phone extension and a record of said data structure;
and
(b) means for retrieving an application name of said associated application
program from said record of said data structure.
16. Apparatus for conferencing a phone call and information associated with
the phone call to a plurality of participants, as recited in claim 14
further comprising means for mapping a trunk to an application.
17. Apparatus for conferencing a phone call and information associated with
the phone call to a plurality of participants, as recited in claim 14
further comprising means for mapping a direct network indirect service to
an application program.
18. Apparatus for conferencing a phone call and information associated with
the phone call to a plurality of participants, as recited in claim 14
further comprising:
(a) means for searching said data structures in said host processor for a
match of said destination phone extension and a record of said data
structure; and
(b) means for retrieving an address of said associated display terminal
from said record of said data structure.
19. Apparatus for conferencing a phone call and information associated with
the phone call to a plurality of participants, as recited in claim 14
further comprising means for updating the data structures with information
associated with said transfer.
20. Apparatus for conferencing a phone call and information associated with
the phone call to a plurality of participants, as recited in claim 14
further comprising means for executing an application program to
initialize the data structures in the host processor.
21. Apparatus for conferencing a phone call and information associated with
the phone call to a plurality of participants, as recited in claim 14
further comprising means for dynamically varying the data structures.
22. Apparatus for conferencing a phone call and information associated with
the phone call to a plurality of participants, as recited in claim 14
further comprising means for displaying information on said plurality of
display terminals before the conference call request is completed.
23. Apparatus for conferencing a phone call and information associated with
the phone call to a plurality of participants, as recited in claim 14
further comprising:
(a) means for accessing the data structures in the host by an application
program;
(b) retrieving information from said data structures; and
(c) performing additional processing based on said information.
24. Apparatus for conferencing a phone call and information associated with
the phone call to a plurality of participants, as recited in claim 14
further comprising means for formatting said communication in accordance
with a logical unit six dot two (LU 6.2) transaction.
25. Apparatus for conferencing a phone call and information associated with
the phone call to a plurality of participants, as recited in claim 14
further comprising means for coordinating a conference call.
26. Apparatus for conferencing a phone call and information associated with
the phone call to a plurality of participants, as recited in claim 14
further comprising means for conferencing the phone call and the
information through the digital switch.
27. Method for conferencing a phone call and information associated with
the phone call to a plurality of participants in a system having a
plurality of phones managed by a digital switch, a plurality of display
terminals, a host processor, and memory means for storing programs and
data structures, each digital switch including memory means for storing
programs and a data structure for uniquely identifying each phone by an
extension, control means for attaching said plurality of phones and
communication means for communicating with the host processor, the host
processor having memory means for storing a communication manager, data
structures and applications programs and communication means for
communicating with the digital switch and the plurality of display
terminals, said method comprising the steps of:
(a) selecting a phone extension to share;
(b) sending the phone extension to share and the originating phone
extension to the host processor;
(c) receiving said communication by the communication manager of the host
processor;
(d) processing said communication and determining an associated application
program and an associated display terminal to link with the phone
extension to share; and
(d) invoking said associated application program to communicate with said
associated display terminal of said originating phone extension to display
information associated with said phone extension to share.
28. Method for conferencing a phone call, as recited in claim 27 wherein
said sharing of the conference information is non-obtrusive to the
conference call.
29. Method for conferencing a phone call and information associated with
the phone call to a plurality of participants in a system having a
plurality of phones managed by a digital switch, a plurality of display
terminals, a host processor, and memory means for storing programs and
data structures, each digital switch including memory means for storing
programs and a data structure for uniquely identifying each phone by an
extension, control means for attaching said plurality of phones and
communication means for communicating with the host processor, the host
processor having memory means for storing a communication manager, data
structures and applications programs and communication means for
communicating with the digital switch and the plurality of display
terminals, said method comprising the steps of:
(a) selecting a phone extension to add to the conference;
(b) sending the phone extension to add and the originating phone extension
to the host processor;
(c) receiving said communication by the communication manager of the host
processor;
(d) processing said communication and determining an associated application
program and an associated display terminal to link with the phone
extension to add to the conference; and
(d) invoking said associated application program to communicate with said
associated display terminal of said phone extension to add to the
conference and displaying information associated with the conference at
said associated display terminal. |
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Description |
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FIELD OF THE INVENTION
This invention generally relates to improvements in data processing
applications in a multiplex communication system and, more particularly,
to the use of a digital switch and host to control the shared access to a
phone call and the terminal display information associated with the phone
call.
DESCRIPTION OF THE PRIOR ART
The past several years have seen the exploitation of digital switch
capabilities, particularly the ability to multiplex voice and data through
the switch.
Traditionally, phone systems were used to manage voice communication.
Functions such as connecting, transferring and forwarding phone calls
became normal features expected in a phone system. The office environment
was incomplete without a phone occupying one corner of an employee's desk.
The phone became the umbilical cord linking the employee to their clients.
Later, computers arrived on the business scene. Applications such as
accounts receivable, accounts payable and inventory control mandated the
use of a display terminal to communicate information to the computer
applications. Soon, the typical office environment included a display
terminal to complement the phone for communicating information to the
computer.
Then, as computer applications became more sophisticated and creative, the
customer service department recognized the value of the display terminal
as a tool and married the telephone with the display terminal to respond
to customer requirements. Soon, customer service personnel became
accustomed to responding to customer inquiries via a telephone as they
entered information into a computer application via a display terminal and
exchanged the display terminal information with the customer.
The display terminal also provided a useful repository of information for
the employee. For example, a client could call to obtain a current
quotation on a stock portfolio. The client might also request prospectus
information on other possible investments. The employee could access a
host database to acquire the stock information; and, if the client wanted
to place an order for additional stock, the employee could transfer the
call to a broker. However, the broker would have to access the same
information again that the other employee had before him on the display
terminal before transferring the call.
While the phone and the display terminal provided a wealth of information,
the coordination of the phone and display terminal has not been handled
effectively in the prior art. An example of a prior art approach to the
problem of transferring phone calls is found in U.S. Pat. No. 4,694,483,
to Cheung, issued Sept. 15, 1987. The Cheung system provides a telephone
call routing system for routing incoming telephone calls to a plurality of
agent display modules. The agent display modules have a list of all phone
calls that are waiting to be handled by the particular agent. Each of the
agent display modules are monitored to balance the calls to each of the
displays. However, there is no display information containing customer
information coordinated with any of the calls. Therefore, this prior art
approach does not provide the unique functionality that the subject
invention provides.
Another prior art approach to data call transfers is found in U.S. Pat.
Nos. 4,535,199 and 4,532,377 to Zink, issued Aug. 13, 1985 and Jul. 30,
1985. The Zink system provides for the redirection of established phone
calls to remotely located digital terminals. The system allows the
transfer of a voice telephone call to a digital terminal to accommodate
the transfer of digital information in response to pressing a DATA button
on the phone. The system is employed to accommodate the use of a single
phone for transferring data and voice. There is no teaching of display
terminal use for the display of data in conjunction with the transfer of a
phone call across a network of digital switches. More specifically, there
is no teaching of shared access to information associated with a telephone
call that is already active.
Another slightly different approach specifically designed for telemarketing
applications is illustrated in U.S. Pat. No. 4,788,682 to Vij et al. The
Vij patent discloses a method for providing a directory number to a sales
person engaged in telemarketing to increase the efficiency of outbound
telemarketing personnel. This patent provides no teaching of transferring
information associated with a call to another interested party in
conjunction with the transfer of the call. Also, there is no teaching of
shared access to information associated with a telephone call that is
already active.
This invention is an improvement on U.S. Pat. No. 4,805,209 to the same
inventors. Features have been added to the original invention to manage
the shared access of information associated with a telephone call. We are
unaware of any similar capability.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to provide a method of
effecting and coordinating the transfer of telephone calls and separate
host based information related to a call through a plurality of digital
switches to a plurality of individuals under the management of a host
processor.
It is a further object of the invention to provide the option of displaying
information associated with a caller on a plurality of display terminals
attached to one of the host processors or the digital switches before the
call is answered by a transferee responder.
It is another object of the invention to allow a caller to join a
conference call and share access to information associated with the
conference call.
It is yet another object of the invention to allow a caller to join a
conference call and share access to information associated with the
conference call in an non-obtrusive fashion.
It is still another object of the invention to use a protocol to simplify
communication between the host and the digital switch.
According to the invention, these objects are accomplished by configuring a
set of host data structures to link phone extensions to particular display
terminals attached to the host and a particular CICS application. The data
structures also contain information regarding the appropriate transfer of
information from the host application to the phone extension across a
network of digital switches. Finally, additional data structures are
provided to facilitate shared access to voice and data extensions
CBX and host have communication managers to facilitate the transfer of
messages using a standard protocol. Also, a standard application manager
is used to coordinate the activities of the system programs and other
preexisting applications. The status of each call is carefully tracked by
the system programs and recorded in logs for later analysis.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other objects, aspects and advantages of the invention
will be better understood from the following detailed description of the
preferred embodiment of the invention with reference to the accompanying
drawings, in which:
FIG. 1 is an illustration of the major functional parts of a Call
Management Control System (CMCS) in accordance with the present invention;
FIG. 2 is a system drawing of a prior art Computerized Branch Exchange
(CBX) similar to the CBX employed in the present invention;
FIG. 3 is an illustration of the hardware shelf layout of the Central
Branch Exchange in accordance with the present invention;
FIG. 4 is an illustration of the Central Branch Exchange Central Processing
Unit shelf slots in accordance with the present invention;
FIG. 5 is an illustration of the Central Branch Exchange Time Division
Multiplex shelf slots in accordance with the present invention;
FIG. 6 is an illustration of the Central Branch Exchange hardware block
diagram in accordance with the present invention;
FIG. 7 is a flowchart of the logic of the Call Management Control System in
accordance with the present invention;
FIG. 8 is a continuation of a flowchart of the logic of the Call Management
Control System in accordance with the present invention;
FIG. 9 is a further continuation of a flowchart of the logic of the Call
Management Control System in accordance with the present invention;
FIG. 10 is a block diagram of the layout of a General Data Stream which is
the communication medium in accordance with the present invention;
FIG. 11 is a list of the function and subfunction codes and their meanings
in accordance with the present invention;
FIG. 12 is a list of the proper groupings of subfunctions and functions in
accordance with the present invention;
FIG. 13 is a list of proper format of the data and time fields and the one
byte flag field of the communication transaction in accordance with the
present invention;
FIG. 14 is a block diagram and field layout of the CALL ABANDONED
transaction in accordance with the present invention;
FIG. 15 is a block diagram and field layout of the CALL TRANSFER
transaction in accordance with the present invention;
FIG. 16 is a block diagram and field layout of the CALL CONNECT transaction
in accordance with the present invention;
FIG. 17 is a block diagram and field layout of the CALL GROUP transaction
in accordance with the present invention;
FIG. 18 is an illustration of the Call Management Control Table in
accordance with the present invention;
FIG. 19 is an illustration of the Extension to Terminal Table in accordance
with the present invention;
FIG. 20 is an illustration of the Trunk to Application Table in accordance
with the present invention;
FIG. 21 is an illustration of the Dialed Number Indirect Service to
Application Table in accordance with the present invention;
FIG. 22 is a state diagram of the call processing in accordance with the
present invention;
FIG. 23 is an overview block diagram of the Call Management Control System
in accordance with the present invention;
FIG. 24 is a detailed block diagram of the applications that comprise the
Call Management Control System in accordance with the present invention;
FIG. 25 is a screen illustration of the View Call Management Control
Tracking Table configuration display in accordance with the present
invention;
FIG. 26 is a screen illustration of the Extension to Terminal Correlation
Table configuration display in accordance with the present invention;
FIG. 27 is a screen illustration of the Trunk ID To Application Correlation
Table configuration display in accordance with the present invention;
FIG. 28 is a screen illustration of the Dialed Number Indirect Service
Trunk Application Correlation configuration display in accordance with the
present invention;
FIG. 29 is a screen illustration of the Agent Extension To Terminal
Correlation configuration display in accordance with the present
invention; and
FIG. 30 is a flowchart showing the logic of shared information transfer
through a network in accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION
______________________________________
Table of Contents
______________________________________
System Overview 10
Hardware Environment 10
Background On The Computerized Branch
10
Exchange (CBX)
CBX Hardware Description 11
SINGLE-NODE COMMUNICATION 12
Time Division Multiplexing 12
Pulse Code Modulation 12
TDM SWITCHING NETWORK: BUS 13
TDM Network 13
Intrashelf Bus 84 13
Intershelf Bus 85 14
Expander Cards 14
TDM Controller Card 15
TDM Controller Card 15
Turnaround Card 16
System Clock 17
Bus Capacity 17
COMPUTER COMMON CONTROL 18
Processor 18
Memory 19
Enhanced Communications Processor
20
DISK SYSTEMS 20
DIAGNOSTIC CARDS 21
System Monitor Card (SMC) 21
Redundant Shelf Monitor 22
Local Shelf Monitor 22
Service Maintenance Port 22
Quad Serial I/O Port 22
CABINETRY AND POWER SYSTEM 23
CMCS Networking Specifics 23
Host Communication Link 24
Host Hardware 24
Software Environment 25
CBX Software 25
Host Software 25
Operating Systems 26
Advanced Communications Facility
26
(ACF)/
Virtual Terminal Application Monitor (VTAM)
Customer Information Control
27
System (CICS)
CICS Applications 27
Functional Description 28
Normal Transfer 29
Blind Transfer 30
Host Activities 30
Call Tracking Program 30
Screen Update Program 31
CMCS Management Information
31
Systems (MIS) Program
CMCS Administration/Maintenance
31
Program
CMCS Customer Application 31
Logic Description
Coordinated Voice and Data Display
32
Call Tracking 32
CMCS Application Structure 35
Call Tracking Application 36
MIS Application 40
Screen Update Application 40
Detailed CMCS Table Analysis
40
Call Management Control Table
40
(CMCT)
Extension to Terminal Table
42
Trunk To Application Table 43
DNIS to Application Table 44
Queue Count Table 44
Message Formats 45
Basic Transaction Flow 45
Display States 46
Administration Application 47
Sample Scenarios 50
Shared Access 54
Shared Access Logic 56
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SYSTEM OVERVIEW
Traditional business telecommunication applications have separate voice and
data components. These business applications can be enhanced by
integrating the voice and data components as described herein.
Referring now to the figures, and more particularly to FIG. 1, there is an
example of the major functional parts of the Call Management Control
System (CMCS). The Computerized Branch Exchange (CBX) 1 is the digital
switch that manages the telephone processing. The CBX 1 interfaces to the
host 3 via an Logical Unit (LU) 6.2 interface 2. Using the example
discussed above, to transfer the phone call from extension 4 to extension
6, the agent performs the normal tasks associated with transferring a
call. The CBX 1 translates the request into a corresponding host display
terminal transfer request transaction from terminal display 5 to display
terminal 7. The transaction is built and sent from the CBX 1 through the
LU 6.2 link 2 to the host 3. The host 3 performs a table lookup to
determine the terminal display 7 associated with the new phone extension
6. Then, the current display transaction that is displayed on the
transferror terminal display 5 is displayed on the new terminal display 7.
A more detailed analysis of the processing is disclosed below.
HARDWARE ENVIRONMENT
Background On The Computerized Branch Exchange (CBX)
An example of a prior art CBX, similar to the preferred embodiment, is
provided in FIG. 2, which illustrates the computer control equipment
associated with the prior art ROLM CBX II 9000. The hardware consists of
redundant memory 10, a shared, switched I/O bus (ISB) 20, various
interface cards 30, disk 40, and redundant processors 50. A remote node
attachment is also provided via the Inter Node Link (INL). A more complete
discussion of the hardware environment is provided in the ROLM CBX II 9000
Business Communications System, published by ROLM Corporation (1986).
CBX hardware for practicing the subject invention is shown in FIGS. 3, 4,
5, and 6. FIG. 3 illustrates the hardware shelf layout of the CBX. Shelf
one 51 is a common control shelf in a redundant system cabinet or another
Time Division Multiplex (TDM) card shelf in a nonredundant system cabinet.
Shelf two 52 is always a common control shelf. Shelves three 53 and four
54 are always TDM card shelves. Air cooling systems and redundant power
systems are provided at 55 to dissipate heat and provide system power.
FIG. 4 illustrates the CPU shelf slots of the common control slot 52. As
shown, there are memory cards 60, processor set 61, shared input/output
(I/O) hardware 62, and disk drive units 63. The processor cards contain
the microprocessors. Additionally, there is a common control motherboard
64 that joins the memory cards 60, the processor set 61 and the shared I/O
hardware 62 to the system bus. The common control motherboard 64 is used
to join the other common control motherboard from the redundant common
control shelf 51 and the TDM shelves 53 and 54.
FIG. 5 shows the TDM shelf slots. The TDM communication cards fit into the
slots shown at 65. The other TDM cards occupy the slots at 68. Slot 70 is
reserved for Line Shelf Monitor LSM which monitors the power supply and
contains the fuses. If LSM detects a power supply failures or fuse
failures, it is reported to error analysis by a scanner reporting a
monitor error. Error analysis then parses specific decision trees to
generate suggested actions.
CBX Hardware Description
The following hardware description discusses FIG. 6, which is a hardware
block diagram of the CBX system. The figure is a functional representation
of the preferred embodiment of the CBX.
SINGLE-NODE COMMUNICATION
Nodes are the modular building blocks of the CBX system. Each node can
function as a stand-alone telecommunication system consisting of the time
division multiplexing (TDM) switching network, processors, cabinet and
power system, and interface cards. A single-node system can expand from
one to five equipment cabinets to accommodate up to 2,000 lines.
The CBX is a digital switching system using TDM and pulse code modulation
(PCM) to support a wide range, of voice, data, and specialty applications.
A 32-bit processor and Random Access Memory (RAM) provide control
intelligence within each node.
Time Division Multiplexing
Multiplexing is a method of using a single communication channel to carry
multiple speech and/or data transmissions simultaneously. The TDM channel
use is alternated between users or between system functions, each
receiving a small portion of channel time (a time slot) in rotation. The
channel seems to be reserved for each individual transmission, but because
of the highspeed channel, it carries many transmissions simultaneously.
Pulse Code Modulation
When the first CBX was shipped in 1975, ROLM was the first vendor in the
industry to use PCM technology. PCM is the process which analog sound
waves of voice conversations are sampled, translated into digital signals,
transported over the TDM network, and reconstructed into analog signals.
The CBX samples voice signals at 8,000 times per second. The samples are
converted into 8-bit binary words, which are transmitted over the data
bus.
This chapter describes the four major components of a single-node
communication system. They are presented in the following order:
TDM switching network
Computer common control
Cabinetry and power system
TDM interfaces to voice, data, trunk, and other resources
TDM SWITCHING NETWORK: BUS
Broadly defined, Bus is the entire TDM switching network. It maintains the
connections established by the processor and passes information between
the common control electronics and the telephones, terminals, and trunks.
The bus is the vehicle for intranode communication.
The bus is a 16-bit, parallel, unidirectional bus that has a capacity of
295 megabits per second (Mbps). It provides 1,152 two-way or full-duplex
communication channels, of which 1045 are available for voice/data
traffic. The system uses the remaining channels for various control
functions, such as setting up phone displays.
TDM Network
The major components of intranode communication are the TDM Network Control
Group. This group consists of the:
Intrashelf Bus 84
Intershelf bus 86 and 87
Expander 80 cards
TDM controller cards
Intrashelf Bus 84
On the back of each TDM shelf is an Intrashelf Bus 84 implemented on the
TDM backplane. The Intrashelf Bus 84 permits communication within a shelf.
On each TDM shelf, one Expander 80 card plugs into each Intrashelf Bus 84.
Expander 80 cards provide the interface between the Intrashelf Bus 84 and
the intershelf bus (ISB).
The total bandwidth available on the Intrashelf Bus 84 is seventy-four
Mbps. Each Intrashelf Bus 84 includes a 16-bit bidirectional data bus, a
10-bit address bus, and an "enable" line to each card. The enable line
eliminates the need for configuring each card with a particular shelf
address, so that interface cards can occupy any slot on the shelf. In
addition, the enable line simplifies address decoding, which increases
reliability.
Intershelf Bus 85
ISB is an integral part of the proprietary Bus structure, handles
communication among shelves through a flat, ribbon cable attached to the
TDM controller (TC 81) card and the Expander 80 cards on each shelf.
The ISB supports a data rate of 295 Mbps over two unidirectional buses: the
source bus 87 and the Destination bus 86.
Expander Cards
If a system has redundant processors, the Expander 80 cards are also
redundant. When one common control side of the cabinet is active, one of
the Expander 80 cards is in use, while the redundant (inactive) common
control side and other Expander 80 card will wait to become active.
Each Expander 80 card contains a connection table for all voice and data
connections affecting its shelf. This frees intrashelf bandwidth for call
data, instead of consuming bandwidth for the address information needed to
make connections.
The Expander 80 cards, TC 81 card, and Turnaround 82 card use the Bus ISB
clock (located on the Turnaround 82 card) for timing the Bus traffic. This
maintains the correct timing relationship between the data, which travels
along the bus, and the clock pulses. The turnaround card also sends out a
pulse at the beginning of each sampling interval. The pulse tells the
Expander 80 card to start again with the first entry in the connection
table.
TDM Controller Card
The Bus TC 81 card, maintains supervision of the processor-ISB-interface
communication. TC 81 cards reside on the common control shelves in cabinet
1 of a CBX node. The TC 81 card is responsible for the following three
activities: loading and verifying the connection table on each Expander
80; configuring the turnaround card and InterNode Link (INL 83) hardware;
and communicating with the various line card groups. The TC 81 card
handles up to 12 Mbps of control information.
The TC 81 card signals its activities by using a bus control field. Control
packets contain addressing, control, and data information for loading the
Expander 80 connection tables and reading the status of line cards.
The TC 81 cards maintain a communication path between the two ends of a
voice or data call. The processor, through the TC 81 card, switches
digitized signals by assigning them to unique time slots on the ISB. The
Bus ISB uses TDM techniques, which enable the ISB to carry a large amount
of simultaneous voice and data transmission.
TDM Controller Card
The Bus TC 81 card, maintains supervision of the processor ISB-interface
communication. TC 81 cards reside on the common control shelves in cabinet
1 of a CBX node.
The TC 81 card is responsible for the following three activities: loading
and verifying the connection table on each Expander 80; configuring the
Turnaround 82 card and InterNode Link(INL 83) hardware; and communicating
with the various line card groups. The TC 81 card handles up to 12 Mbps of
control information.
The TC 81 card signals it activities by using a bus control field. Control
packets contain addressing, control, and data information for loading the
expander connection tables and reading the status of line cards.
The TC 81 card maintain a communication path between the two ends of a
voice or data call. The processor, through the TC 81 card, switches
digitized signals by assigning them to unique time slots on the ISB. The
bus uses TDM techniques, which enable the ISB to carry a large amount of
simultaneous voice and data transmission.
Turnaround Card
As its name implies, the Turnaround 82 card turns the data around on the
bus. The Expander 80 card on the transmitting card's shelf places a data
word on the source bus 87. The data word travels to the right until it
encounters the Turnaround 82 card, which receives the word and retransmits
it ("turns it around") to the Destination bus 86. Then the Expander 80 on
the destination shelf captures the word and sends it on to the proper
card.
The advantage of using the turnaround card is that information
retransmitted in an individual time slot to the Destination bus 86 and the
receiving card can be completely different from information received in
that time slot from the source bus 87 and the transmitting card. This
doubles the traffic capacity of the switch by allowing two internode
conversations to take place in a single time slot on the bus.
To further understand how this occurs, imagine that a conversation is
taking place on telephones with connections in node A. The system
transmits a voice sample on the node-A source bus 87, and the sample
encounters the Turnaround 82 card, which places this sample on the
destination part of the same bus. The time slot on the destination part of
the node-A bus has now become free.
The Turnaround 82 card can fill this empty slot with a voice sample from
the other end of the conversation. In this way, the signals from both ends
of the conversation can occupy the same time slot simultaneously.
System Clock
In each node of a multinode CBX system, the system clock provides timing
for the TDM network via the Turnaround 82 card. It also synchronizes INL
83 operation between nodes. The source of this clock can be its own
internal system, or it can synchronize from an external T1 interface
trunk. The system clock conforms to Stratum 4 of the Bell Network
Synchronization Plan.
Bus Capacity
The new Bus provides the CBX with 2,304 timeslots per node. Bandwidth is
the measure of voice and data traffic capacity in the CBX. The clock speed
of the Bus 16-bit parallels backplane is 18,432 MHz. The total bandwidth
of the system is, therefore, 18,432 megahertz/second.times.16
bits/cycle=294.912 Mbps.
To restate this in terms of communication channels since the CBX sampling
frequency is 8 kHz, the bandwidth in each direction of a communication
channel of the 16-bit backplane is 8,000 samples/second.times.16
bits/sample=128,000 bps (128 Kbps).
Note: Each sample is actually 8 bits; however, 16 bits are used to allow
for future expansion of function. Therefore, the total bandwidth in a node
with Bus is 1,152 channels.times.128 Kbps.times.2 connections/full-duplex
channel=294,912 Mbps in each node.
Thus, the total bandwidth for a 15-node system with bus is 15
nodes.times.295 Mbps/node=4.425 Gbps (or 4,425,000,000 bps).
COMPUTER COMMON CONTROL
The CBX offers the advantage of computer common control. With the stored
programs of computer common control, it is easy to update features as
business needs change. This provides greater flexibility and reduces the
cost of feature additions and other changes that may be made in the
future.
The computer common control group directs all activities within the CBX
system. A single-node CBX supp | | |
