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Description  |
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TECHNICAL FIELD
This invention relates to communication systems and particularly to
conferencing arrangements in a telecommunications network.
In a more particular aspect, this invention relates to automatic dial-up
conferencing arrangements whereby a customer can originate and control a
multiparty conference for voice and data terminals. In a still more
particular aspect, this invention relates to combined voice/data
conferencing arrangements which are controlled by the conference
originator under the guidance of voice prompts from a processor controlled
announcement system.
BACKGROUND OF THE INVENTION
Communication networks have become a valuable measure for use in exchanging
information among geographically separated customers. With increasing
costs for travel and lodging, conferencing arrangements offer an
alternative to face-to-face meetings by allowing all conferees to
participate in routine meetings which can be called on short notice.
While many teleconferencing arrangements have been available in the past,
they lack certain features found in the present arrangement.
In one form of prior art conference arrangement, the originator of the
conference must call an operator and give the operator the telephone
numbers of all conferees and the time that the conference is to be held.
If changes are to be made during the conference, such as adding another
party, the operator must be signaled and must interrupt the conference
while establishing a connection to the new conferee.
While these arrangements are suitable for their intended purpose, they
require the services of an operator to establish and supervise the
conference in order to ascertain if any changes are to be made. This puts
an additional work load on the operator's position, and the operator
spends an inordinate amount of time dialing each conferee and waiting for
each conferee to answer. Thus, to alleviate operator position work load
and render more privacy to a conference service, it is desirable to
automate many of the functions associated with conference calls.
Automatic conference arrangements are also known in the prior art. In
certain automatic group call arrangements, the conference originator can
dial a preassigned code to summon the group of conferees designated by the
code. Also, in typical dial-up conferences, the originator can dial each
conferee in a manner similar to the operator's procedure described above.
Of course, the group call arrangement lacks the flexibility of permitting
parties to be added to the conference. On the other hand, the dial-up
conference arrangement may be troublesome for the originator particularly
when complicated dialing procedures are involved to establish a large
conference or to implement numerous special service features such as
selectively conferencing data terminals which may or may not be associated
with the customers participating in an audio conference.
SUMMARY OF THE INVENTION
The foregoing problem is solved and a technical advance is achieved by a
dial-up audio/data conference arrangement which automatically prompts the
originator as to the proper procedures for implementing the conference
service.
More specifically, the invention is embodied in a network services complex
comprising an audio bridge system, a data bridge system, a data store
announcement system, and a tone receiver system. Each of the above systems
is processor controlled, and a main processor system oversees the
functioning of the entire complex.
In operation, a customer initiates a conference by dialing a special
conference code. The call is routed to the network services complex and
the network services complex responds by prompting the caller with
instructions on what action must be taken next. The prompts are audio
messages composed and generated by the data store announcement system at
the request of the main processor system for playback to the conference
originator.
Thus, the customer dynamically interacts with the network services complex
by responding to the prompts using the keyset of his telephone station. In
accordance with a feature of the invention, the system will recognize
invalid responses from the originator and automatically prompts the
originator with new messages so that the user can take corrective action.
According to a further feature of the invention, when the network services
complex detects that the user is making too many mistakes and may get
frustrated, an operator is automatically summoned to assist the user. The
operator is then automatically apprised of the nature of the originator's
difficulty so that the operator may render the proper assistance to the
conference originator. In accordance with still another feature of the
invention, the conference originator can selectively establish conference
channels to telephone stations and data terminals, independently, so that
customers equipped with audio and data capabilities can converse with each
other and also exchange graphic information.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a block diagram of a telephone network having a toll switching
system equipped with a network services complex for providing conference
services;
FIGS. 2-4 show a more detailed block diagram of the audio bridge portion of
the network services complex with FIG. 3 showing the audio-bridge
processor and FIG. 4 showing the audio bridge switching hardware;
FIG. 5 shows a more detailed block diagram of the data store used for
storing announcements for the network services complex;
FIGS. 6-10 show the data bridge system of the network services complex with
FIG. 7 showing a typical data port, FIG. 8 showing a typical data link
processor, FIG. 9 showing the port data interface and FIG. 10 showing the
data bridge processor;
FIG. 11 shows the main processor system of the network services complex;
FIGS. 12-20 show a flow diagram of the overall operation of the system; and
FIG. 21 shows the legend of the symbols used in the flow diagram.
GENERAL SYSTEM DESCRIPTION
The general organization of a system employing the invention is illustrated
in the block diagram of FIG. 1 which shows a typical communications
network having a toll switching system 102 which serves local telephone
central offices 103 and 104. Central offices 103 and 104 contain the
switching apparatus for providing telephone service to customer stations
105 and 106, respectively and data service to data set 136 and graphics
unit 127. Connected to switching system 102 is a network services complex
100 for providing special services such as audio/data conferencing.
Network services complex 100 includes NSC processor 101, data store system
125, input/output controller 130, audio bridge system 128, data bridge
system 135, a plurality of tone receivers such as 138, and other units. As
will be described in more detail below, one of the functions of complex
100 is to provide audio/data conferencing with announcements and
instructions to customers over the telephone network via the toll and
local switching offices.
Toll switching system 102, as depicted in FIG. 1, is a typical electronic
switching system, such as, the No. 4 ESS which is manufactured by the
Western Electric Company, Incorporated. This switching system is described
in detail in the Bell System Technical Journal, Vol. 56, No. 7, September
1977, and need not be fully described herein for the reader to understand
the present invention.
Switching system 102 comprises a network 107, a central processor 108,
voice interface unit 109, digroup terminal unit 110, signal processors 111
and 112, and miscellaneous equipment units that have not been shown to
simplify the drawing.
Network 107 has a time-space-time switching configuration utilizing time
slot interchange (TSI) units 113-116 and time multiplex switch (TMS) unit
117.
TMS 117 is a two-stage switch array comprised of solid state crosspoints
which provide a multiplicity of unidirectional paths between its input and
output. Each network connection through TMS 117 is made in terms of a pair
of unidirectional paths in one of the 128 time slots sharing the paths on
a repeating basis at an [KHz rate. The switches are controlled by
information contained in time slot memories and this information is placed
in the memory by the processor under the control of call processing
programs.
The TSI units 113-116 provide the initial time-space and final space-time
stages of the network 107. The time slot interchanger receives incoming
pulse code modulated samples over analog and digital facilities in a
DS-120 format where 120, 8-bit PCM channels are multiplexed with 8
maintenance channels to form a 128 time slot frame. The receiving portion
of the time slot interchange buffers the incoming links to allow
synchronization of the data with the network timing and performs the
initial time-space switching before transmitting data to the TMS. After
passing through the TMS, the data is returned to the same TSI or another
TSI where the final space-to-time conversion is performed. The TSI then
reloads the data onto outgoing DS-120 links where it is transmitted to the
appropriate analog or digital facility.
Access to the switching network 107 is via serial pulse code modulation
links each accommodating 120 voice channels. However, central offices 103
and 104 can be connected to toll switching system 102 via analog or
digital transmission facilities. Thus, as seen in FIG. 1, local central
office 103 and operator position 137 are connected to the toll office over
the digital facilities which terminate in digroup terminal unit 110, while
local office 104 is connected via analog trunks to voice interface unit
109. Digroup terminal 110 performs the multiplexing and demultiplexing
between the interoffice transmission facilities and network 107 and also
processes signaling information via signal processor 112.
The analog trunks are terminated in a voice interface unit such as 109
whose principal function is analog-to-digital conversion (and vice-versa)
plus formatting digital data for the TSI units. Voice interface unit 109
communicates with the central control via signal processor 111.
Signal processor 111 is a directed processor under the control of central
control 118 and provides the scan, distribute and digit reception tasks
for analog trunks. Signal processor 112 performs the equivalent tasks for
the digital trunks except that instead of physical scan and distribution
points, the supervisory states of each trunk are stored in a memory in a
signal processor.
The majority of the logic, control, storage and translation functions
required for the operation of the toll switching system are performed by
central processor 108. Central processor 108 is a data processing facility
and can functionally be divided into a central control 118, program store
119, call store 120, file store 121 and other apparatus that has not been
shown to simplify the drawing. A typical processor suitable for use in the
illustrative toll switching system is described in the Bell System
Technical Journal, Vol. 56, No. 2, February 1977.
The program store 119 contains programs that are normally resident in the
system while call store 120 contains transient data relating to calls in
progress. File store 121 is a source of office data and programs, and
store 121 will retain the data in the event of a power or hardware
failure. The file store is also used to replenish program stores that
become faulty and lose their data.
Central control 118 is the information processing unit of the system and
executes the program instructions resident in program store 119 using the
call processing data in call store 120. Central control 118 communicates
with the peripheral units via bus 122.
As mentioned above, interoffice signaling information is extracted from the
transmission paths of analog and digital trunks by signal processors 111
and 112, respectively, and used by central control 118 for call
processing. However, the signaling for certain trunks may be transmitted
between the offices over a common data link separate from the transmission
paths using a common channel interoffice signaling system. A typical
common channel interoffice signaling system is described in the Bell
System Technical Journal, Vol. 57, No. 2, dated February 1978, and is
represented herein by CCIS blocks 123 and 126 and data link 132.
Coupled to the toll switching system is the network services complex 100
comprising a main processor system including NSC processor 101 and
input/output controller 130, a data bridge system 135, an audio bridge
system 128, CCIS terminal 126, DS-1 interface 129, time slot interchange
124, data store announcement system 125 and a plurality of tone receivers,
such as 138. Network services complex 100 can also include other units
such as additional audio conferencing bridges, speech recognition systems,
data processing units, etc.
It is intended that network services complex 100 function with many
different types of switching systems to provide several special services
in addition to those mentioned above. As such, complex 100 has been
designed to connect to a switching system via conventional interoffice
trunks 131 and a CCIS data link 132. The interoffice trunks 131 serving
complex 100 are digital facilities similar to the trunks between toll
office 102 and local office 103 as described above and the data link 132
and its CCIS terminals are similar to those described in the 1978 Bell
System Technical Journal cited above. Although these terminals are
referred to as CCIS terminals, it is not essential that they be integrated
in the CCIS signaling system of the network.
The network services complex is modularly designed to allow for various
service units to be added. All units are interconnected over a data bus
133 and a control bus 134. The control bus is used by the NSC processor
101 to communicate control, status and error information with the various
units in the complex. Program associated data, billing data, etc., which
is distinguished from customer data to be conferenced is also transmitted
over control bus 134. Data bus 133 consists of a transmit bus and a
receive bus and each bus is a 256 time slot, time-multiplexed PCM data
bus.
Interface 129 connects the T1 lines from toll switching system 102 to time
slot interchange unit 124 which under the direction of processor 101
switches any time slot in the receive T1 bus or the transmit portion of
data bus 133 with any time slot on the T1 transmit bus or the receive
portion of data bus 133. Thus, the interface 129, time slot interchange
124, and bus 133 provide the path for the exchange of voice, data,
announcements, and inband signaling between the toll switching system 102
and units of the network services complex.
The network services complex 100 is controlled by NSC processor 101 which
performs or initiates all call processing, maintenance, fault recovery,
diagnostics and audits for the entire complex. Processor 101 also
interfaces with CCIS terminal 126 to transmit and receive messages from
the host toll switching system 102.
As mentioned above, the network services complex can be equipped to furnish
many services. For purposes of illustration, let it be assumed that the
complex is equipped for dial-up audio/data conferencing with voice
prompting. Accordingly, the complex comprises an audio bridge system 128
which is used for combining the digital voice samples of speakers on a
conference for distribution to other participants of the conference. Data
bridge system 135, on the other hand, receives data from each conferee's
data terminal and distributes the data to the other conferees at the
correct speed, in the proper format, etc. The term, data, when used with
respect to information transmitted by a customer, is meant to include
digital representations of video signals, facsimile, signals from devices
such as electronic chalk boards, etc., which is separate from the voice
and tone signals transmitted by the customer.
Network services complex 100 also includes a data store system 125 for
furnishing announcements to instruct the customers in the use of the
special services, and a tone receiver 138 which receives the tone signals
representing digits generated by the customer in establishing and
controlling a conference.
The control interface between the network services complex systems and the
toll switching system 102 is via a main processor system including NSC
processor 101, input/output controller 130, and CCIS type terminal 126. It
is via this path that orders are exchanged between the network services
complex and the toll switching system.
DS-1 interface 129 in this embodiment provides an interface for up to five
T1 lines (120 channels or time slots) which terminate on time slot
interchange unit 124. The time slot interchange unit in turn, functions to
switch these circuits with 256 time slots on time multiplex data bus 133
to interconnect the channels with the various service units in network
services complex. Thus, voice, data, and signaling information incoming
over the toll telephone network from a conferee is forwarded via interface
129, and time slot interchange 124 to the audio and data bridges for
conferencing or to the tone receiver for digit detection and collection
while announcements and tones from data store system 125 and conference
data from the bridges are transmitted back via the time slot interchange
over the toll network to the conferees.
Conference calls are established by using a conventional telephone station
and dialing a special conference code assigned to the conferencing
service. To facilitate end-to-end signaling, it will be assumed that the
customer station is equipped with a keyset for generating dual-tone
multifrequency signals.
The telephone call is handled in the usual manner through the network and
routed according to the dialed digits to the nearest toll switching system
equipped for conferencing, such as system 102. Toll switching system 102
accesses the network services complex by transmitting a message over data
link 132 to CCIS terminal 126 and ascertains if conferencing facilities
are available. If facilities are available, the call is handed off to the
network services complex by extending the conference originator's talking
path via a channel in T1 carrier link 131, time slot interchange 124 and
over the time multiplex data bus.
Recognizing a request for a conference, NSC processor 101 requests an
identification of the calling line and transmits an order over bus 134 to
data store system 125 ordering a particular message prompt to be played to
the customer. This prompt would advise the customer that he/she is
connected to a conference facility and request the customer to dial
certain codes to indicate whether this is an audio only, data only, or a
combined audio/data conference. The prompt would also ask the originator
how many parties will be included in the conference.
Data store system 125 responds to the order from processor 101 by loading
the appropriate messages in a playback buffer and transmitting the
messages over the time multiplex data bus 133 and time slot interchange
124 to the conference originator. Processor 101 also causes a tone
receiver 138 to be connected in a different time slot over the time
multiplex data bus to the conference originator. The receiver monitors the
originator's line for the reception of tones from the caller.
The customer now dials (keys in) the codes satisfying the requirements for
his/her conference. Tone receiver 138 detects each digit and forwards it
to processor 101. Assuming that this is a combined audio/data conference,
processor 101 reserves audio ports in bridge system 128, data ports in
bridge system 135, and then sends an order to the data store system 125
causing the next message prompt to be transmitted to the originator.
This prompt will tell the conference originator the code that should be
dialed followed by the telephone number of the conferee to be added to the
conference. As each telephone number is received via the tone receiver 138
and forwarded to processor 101, processor 101 initiates a call over its
data link 132 to toll switching system 102 requesting that the toll
switching system establish a call to the designated conferee and connect
that conferee to a channel selected in T1 link 131.
As each leg is established under the direction of processor 101 and the
called conferee answers, the conference originator can converse with the
conferee announcing that he/she is about to be added to the conference.
Similar legs are established from data bridge system 135 to the data
terminals of each conferee.
In accordance with a feature of the invention, if the conference originator
does not respond with the correct code when prompted by the network
services complex, additional prompts will be supplied to assist the
originator in completing the call in the correct manner. Should the
originator make too many errors in dialing the appropriate calls for the
conferee, processor 101 will signal the toll switching system 102 to
establish a communication path to the operator at position 137. The
operator is then interconnected with the originator of the conference.
When the operator is summoned, signals will be transmitted to the operator
indicating the nature of the problem the originator is experiencing.
DETAILED DESCRIPTION
The invention can better be understood by a more detailed description of
each of the major elements of the apparatus as shown in FIGS. 2-11
followed by a description of the sequence of operation of the equipment
with respect to the flow diagrams in FIGS. 12-21.
1. Main Processor System
The main processor system for the network services complex is shown in more
detail in FIG. 11. The main processor system comprises NSC processor 101,
memory 1100, input/output controller 130, and display 1101 which are
interconnected over system bus 1103. The main processor system is a
distributed processor which is responsible for all call processing,
maintenance, fault recovery, certain diagnostics and audits for the
network services complex as a whole. The main processor system also keeps
track of all system resources such as what ports are assigned to a
particular conference, the status of all ports and receivers, the
identification of available announcements, etc.
Communication with the toll switching system 102 is via CCIS terminal 126
which accesses processor 101 via a direct memory access channel, and
processor 101 distributes orders to and receives replies from the
peripheral service units (such as the data bridge, the audio bridge, etc.)
via input/output controller 130 which acts as a direct memory access
controller for the processor. Using a shared area of memory 1100,
controller 130 transfers messages between the peripheral service units and
processor 101.
The units within the main processor system communicate via system bus 1103
in a master-slave relationship. Central processing unit (CPU) 1104, I/O
processor 1111, and a memory refresh controller (not shown), acts as
masters with the other units acting as slaves. Contention between bus
masters is resolved by a bus arbiter arrangement in a well-known manner.
The NSC processor 101 comprises CPU 1104, interrupt controller 1106, CCIS
interface 1105, timer 1107, and unit cut off registers 1108.
Interrupt controller 1106 responds to signals from equipment such as timer
1107 and controller 130. It will be noted that CCIS interface 1105 resides
on the system bus to permit any master on the bus to access a random
access memory (RAM) which resides in the terminal 126.
As mentioned above, the serial control bus 134 interconnects the main
processor system with the peripheral service units for control information
and time multiplex data bus 133 interconnects the units for data flow.
These units can be disabled and forced off the bus by unit cut off
registers 1108 under the direction of CPU 1104.
The input/output controller 130 acts as a direct memory access controller
for memory 1100 and all service unit operations. In addition, it permits
maintenance personnel to access the system via a maintenance terminal
1177. I/O processor 1111 accesses its own resident bus 1119 via address
and data transceivers 1110, and it accesses the system bus 1103 via
address and data transceivers 1109.
I/O processor 1111 has its own memory 1114 for program storage and its own
interrupt controller 1112. It is via interrupt controller 1112 that the
peripheral units such as the audio bridge, data bridge, etc., gain access
to main processor system of the network services complex.
All communication of the control information between the main processor
system and the other units of the complex is via serial control bus
interface 1115 and control bus 134. The main processor system units acts
as a master on the control bus with the audio bridge system, data bridge
system, data store system tone receivers, time slot interchange unit, etc.
acting as slaves. Messages from the main processor system are formatted
with a destination address of the peripheral system to which the message
is directed, followed by an operation code which specifies the function of
the message and a data field containing the contents of the message. If a
peripheral unit such as the data bridge wishes to utilize the control bus
134, it signals over a dedicated interrupt lead to interrupt controller
1112, and the main processor system can grant control of the bus with the
next message it sends over the bus.
2. Data Store System
As mentioned above, data store 125 is provided to furnish announcements
over the telephone network to instruct customers in the use of the special
services furnished by the network services complex. In general, data store
125 receives requests for announcements in the form of orders from NSC
processor 101 over control bus 134, acknowledges the requests and plays
the announcement back over bus 133 in a time slot designated by processor
101.
The apparatus of data store 125, which will now be described, is more fully
disclosed in FIG. 5. As shown in FIG. 5, data store 125 is a processor
controlled facility comprising a plurality of communications registers
501, playback and record buffer systems 502 and 503, peripheral interface
controller 504 and disc unit 505 with its associated control, data/clock
and parallel/serial interface units 506-508. Audio information transmitted
from time slot interchange 124 (shown in FIG. 1) via 8-bit serial/parallel
multiplex bus 133R is received in record buffer system 503 in encoded PCM
format. Similarly, audio information is played back via playback buffer
system 502 and transmit bus 133T to time slot interchange 124. Data
transfer occurs at a 64Kb/s rate per channel.
Orders received from NSC processor 101 and replies generated by peripheral
interface controller 504 are transmitted over control bus 134 at a 2Mb/s
rate.
Orders for the play back of various messages which are stored in disc unit
505 are executed by reading from sectors of the disc 505 into a plurality
of the playback buffers of the playback buffer system. In this embodiment,
each playback buffer can contain up to two seconds of information for each
playback channel and the data store as a whole can accommodate up to 32
channels of play back, with seven of these allocated to playing
repetitively, two-second announcements and signals such as a tone. The
32nd channel is used for internal maintenance.
Each playback channel of the data store will be assigned a time slot on bus
133T and of course, a plurality of data stores, such as 125, can be added
to the bus to increase the overall voice storage and playback channel
capacity of the network services complex. Most of the intelligent logic
for the data store resides in the peripheral interface controller 504.
Controller 504 is a high-speed sequencer driven controller which performs
all common arithmetic and logic functions for control purposes within the
data store. Controller 504 is driven by a firmware program contained in
the microprocessor control store 509. Controller 504 communicates with
other equipment in the data store such as communications registers 501,
buffer systems 502 and 503 and the disc unit via internal bus 525.
Periodically, sequencer 510 in controller 504 generates an address to read
a word from store 509. This word is read into instruction register 511 in
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