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Description  |
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CROSS-REFERENCE TO RELATED APPLICATIONS
The following U.S. Patent, which is assigned to the same assignee as the
instant application and filed concurrently therewith, has related subject
matter:
(1) "Integrated Message Service System", U.S. Pat. No. 4,612,416.
FIELD OF INVENTION
This invention relates to message service systems and, in particular, to a
voice mail service system that is integrated with other message services.
The telephone switching system that serves the subscriber provides a
number of message services (voice mail, message center, etc.) and
integrates the control of these services so the subscriber is provided
with a single indication of the location of all messages awaiting
retrieval on all message service systems.
BACKGROUND OF THE INVENTION
Message services is the term used to collectively identify the various
office automation systems associated with a telephone switching system.
These systems are used to improve the productivity of the white collar
worker in an office environment by providing an asynchronous voice (or
short text message) communication medium.
The Voice Mail Service (VMS) system is one example of these message
services. The voice mail service system offers two distinct communication
features: Voice Mailbox (VM) and Call Answering (CA). The voice mailbox
feature involves a telephone user calling the voice mail service system by
dialing an access code using the touch-tone pad on the station set,
identifying one or more message recipients who are also connected to the
PBX by dialing their station numbers using the touch-tone pad, and leaving
a voice message for later delivery by the voice mail service system to the
designated recipients. The delivery of the voice message may be immediate
or at a scheduled time specified by the message originator. The delivery
is passive in that the voice mail service system places the message in a
mailbox assigned to each identified recipient and activates the
recipient's message waiting indicator on his/her telephone set instead of
actively calling the recipient to playback the message. The recipient may
then access the voice mail service system to save the message for
subsequent action, listen to the message, delete it, append comments and
route the message to other recipients, or reply and return the message to
the originator.
The call answering feature of voice mail service is geared to the
convenience of the message recipient, unlike the voice mailbox feature
which is geared towards aiding the message originator. The nonavailability
of an individual to answer a telephone call results in that call being
redirected to the voice mail service system call answering feature. The
caller receives a prerecorded message from the absent individual and can
then leave a voice message in the absent individual's voice mailbox.
The difficulty with existing voice mail service systems is that a user must
query this system as well as all the other message service systems to
locate and retrieve all messages. In the case where the user's telephone
station set is equipped with a single message waiting indicator, the
lighted indicator indicates only that any one or more of the message
services contains an unretrieved message. The user must still poll all
message services to locate and retrieve these messages.
SUMMARY OF THE INVENTION
The subject integrated message service system provides a user with an
indication of which message services contain unretrieved messages whenever
a user accesses any of the message services. The telephone switching
system provides coordination for all the message services and also
controls the message waiting indicator on each user's telephone station
set. The telephone switching system maintains a translation memory for
every extension served by the telephone switching system to store a
translation table indicating the types of message services assigned to the
user and data in the translation table also indicate whether this
subscriber has or does not have unretrieved messages in the assigned
message service systems. When a subscriber accesses any one of these
message systems, the accessed message service system receives a message
from the telephone switching system via a data communication interface
unit to provide the current message waiting status for each message
service. If messages exist on other message service systems, an
announcement (in the case of voice mail service) will tell the subscriber
which message service systems to contact next. The telephone switching
system provides the logical "OR" of the indications from the various
message service systems to control the message waiting indicator for each
extension.
The system processor of the telephone switching system performs the message
waiting indication database management function for the various message
service systems. The system processor is connected via a data
communication interface unit to the processor in each message service
system. The system processor can thereby communicate with each message
service system to collect information about unretrieved messages for each
telephone extension served by the telephone switching system. The system
processor updates the translation table in response to "message created"
or "message accessed" signals from the various message services.
Whenever a subscriber dials the access number for one of the message
service systems, the system processor activates the switching network of
the telephone switching system to establish a voice communication
connection to the designated message service system. The system processor
concurrently transmits a data message via the data communication interface
unit to the processor which controls the designated message service
system. This data message identifies the calling party extension and the
unretrieved message status of the calling party. The designated message
service system can thereby provide an appropriate response to the calling
party to indicate the location of unretrieved messages in all the message
service systems.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 Illustrates the subject integrated message service system in block
diagram form;
FIG. 2 illustrates the feature and voice storage processor elements of the
voice mail service system in block diagram form;
FIG. 3 illustrates the data channel interface unit in block diagram form;
and
FIG. 4 illustrates the memory structure in the telephone switching system
that supports the integrated message service feature.
DETAILED DESCRIPTION
The subject integrated message service system and the business
communication system of which it is a part is shown in block diagram form
in FIG. 1. A key element of this business communication system is a stored
program controlled telephone switching system 100 which provides business
communication services to a plurality of subscriber stations T100-Tm.
Included in telephone switching system 100 is a switching network 101 for
establishing communications connections among subscriber stations T100-Tm.
A system processor 102 controls the operation of telephone switching
system 100. The business communication system of FIG. 1 includes several
message service systems such as voice mail service system 110 for
electronically storing and forwarding voice messages and message center
service system 120 for having operators at consoles 121-12n record message
for callers. These systems are known in the art and, to illustrate the
subject integrated message service system, voice mail service 110 will be
described in further detail below.
Telephone switching system 100 provides each user with access to message
services such as voice mail service. Users can directly call voice mail
service system 110 or can redirect their incoming calls to voice mail
service system 110. Telephone switching system 100 provides a data
communication interface unit (DCIU) 103 and a data link 105 connection to
voice mail service system 110 to exchange call related information such
as: new call, call disconnect, message waiting indication control, etc.
A user initiates an access to voice mail service system 110 to, for
example, generate a voice mail message by going off hook on the user's
associated telephone station set T100 and dialing the voice mail service
system access number. The system processor 102 receives and decodes the
dialed number in well-known fashion and connects telephone station set
T100 to one of the voice mail service access trunks 104 via switching
network 101. This establishes a voice communication connection from
telephone station set T100 via switching network 101 and voice mail
service access trunks 104 to voice mail service system 110.
At the same time that this voice communication connection is being
established, system processor 102 transmits a data message identifying the
calling party to voice mail service system 110 through the data
communication interface unit 103 and over data link 105. Once a data
message comes over data communication interface unit 103 from telephone
switching system 100 announcing a new call, voice storage processor 111
and feature processor 112 interact directly with the user to provide the
required features. The voice storage processor 111 controls the sequencing
of that call until a disconnect is received. The voice storage processor
111 is comprised of many different elements working together to provide
voice encoding capability. The hardware necessary to digitize voice and
successfully buffer it before storing it in data base processor system 113
is part of voice storage processor 111.
Feature processor 112 provides the various system level features associated
with voice mail service, such as mailing lists, message delivery, etc. The
data base processor 113 serves as a mass storage element to store all the
digitally encoded voice signals as well as control algorithms used by
voice storage processor 111 and feature processor 112. Additional details
of voice mail service system 110 are disclosed below.
In the subject integrated message service system, system processor 102
maintains a record of the location of messages for each user in telephone
switching system 100. The data message (noted above) that is transmitted
by system processor 102 to voice storage processor 111 via data
communication interface unit 103 and data link 105 on the initial call
connection to voice mail service system 110 includes data relating to the
presence/absence of messages stored on the various message service systems
(such as message center 120) for the user at telephone station set T100.
Voice mail service system 110 provides a prerecorded announcement to the
user to note the location of these messages. Feature processor 112
receives the data message from system processor 102 and determines what is
the required content of the prerecorded announcement based on the data in
the data message. Feature processor 112 then activates voice storage
processor 111 to retrieve the appropriate prerecorded announcement from
data base processor 113 and provide same to the user. The details of the
call completion, data message structure and message retrieval will be
discussed below. The structure of voice mail service system 110 and data
communication interface unit 103 are first described to provide background
for that description.
Voice Mail Service System
The voice mail service system 110 is disclosed in block diagram form in
FIG. 2. This system comprises three main elements: voice storage processor
111, feature processor 112 and data base processor 113 (not illustrated).
Broadly stated, the voice storage processor controls the following:
a. Keeping track of control information about current voice messages being
played or recorded, including where in the message the caller stopped
playback, and whether the caller is playing back or recording.
b. Opening voice channels in preparation for recording or playback.
c. Closing voice channels to end recording or playback.
d. Controlling playback speed.
e. Controlling playback volume.
Feature Processor 112 controls the following functions:
a. Controlling message headers--how they are read and created.
b. Concatenating two messages together, or duplicating a voice message.
c. Erasing a message (includes telling the data base processor system to
deallocate all extents associated with this message).
d. Rewinding a message.
e. Keeping track of problems so that information can be provided to the
caller when questions arise.
f. Retrieving messages from a caller's mailbox and preparing to play back
both message summary and the message body.
g. Skipping to the next message (if any).
h. Saving a message for later playback (becomes an old message in the
mailbox).
i. Verifying the password typed in by the caller.
j. Retrieving distribution lists to later send out messages.
k. Controlling the delivery of messages.
l. Storing a working message, one per subscriber.
m. Retrieving initial lists of all messages (both new and old) in a user's
mailbox.
n. Deleting a message and clearing up the disk space for later use.
o. Retrieving a list of outgoing messages to report the status of each.
p. Canceling the delivery of a piece of undelivered mail.
q. Notifying system processor when all messages are accessed.
Data Base Processor
Data base processor system 113 is a back-end file system and data base
machine. As a back-end processor, data base processor system 113 serves to
offload file system and data base operations from voice storage processor
111. It also provides all the non-volatile storage used by the voice
storage processor 111.
Both voice and non-voice files are stored by data base processor system 113
for voice mail service system 110. The voice files will include
announcements and messages. The non-voice files will include system
programs, system data, and user data. Data base processor system 113
provides basic file system support for voice mail service with functions
which include, but are not limited to: File system management functions
(e.g., create, modify, delete, backup, recover, and report status of files
and file systems); File manipulation functions (e.g., insert, modify,
delete data in a file); File level concurrency control functions; Data
base processor system administration functions; Data base processor system
maintenance functions.
Voice Processors
The voice processors (220-22n) and the voice ports (210-21n) take care of
the following physical operations: Touch-tone signal receiving; Answer,
disconnect; Ring detection; Digit queuing; Bandwidth compression (compress
the voice data from 64k bits/s down to 16k bits/s); Silence compression
(encode the length of long silences so that the encoded length value
rather than the actual silent interval can be stored on disk); Playback
speed control (speed-up or slow-down the rate of playback); Playback
volume (louder or softer); Automatic gain control; Per port timing
(inter-token timing); Freezing a voice channel to temporarily stop
recording or playback; Applying audible tone right before recording to
signal the caller to begin; Monitoring how much is recorded, and freezing
the channel when a maximum is reached.
Voice Interface Operation
When telephone switching system 100 establishes a voice communication
connection from the user at telephone station set T100 to one of voice
mail service access trunks 104, ringing will be applied to the selected
voice mail service access trunk. No action will be taken by voice mail
service system 110 due to this ringing signal. The call will be answered
without regard to the presence or absence of ringing on the associated
line when a connect message identifying an incoming call on a voice mail
service access trunk 104 is transmitted to voice mail service system 110
by system processor 102 via data communication interface unit 103 and data
link 105. After closing the loop on the selected voice mail service access
trunk 104 as an answer signal, voice storage processor 111 will monitor
the flow of loop current on this trunk to insure a complete connection.
When telephone switching system 100 disconnects a call from a voice mail
service access trunk 104, no immediate signal is sent over the trunk to
voice mail service system 110. If a disconnect message identifying an
existing connection is received by voice storage processor 111, the loop
will be opened on the voice mail service access trunk 104 for a time
sufficient to be recognized as an on-hook signal by telephone switching
system 100.
The user at telephone station set T100 activates the desired feature of
voice mail service system 110 in well known fashion by simply dialing a
code designating the desired feature. To illustrate, assume the user
wishes to create a voice message for transmittal to a number of
destinations. The user dials the "create" digit on telephone station set
T100, which dialed digit is transmitted via the voice communication
connection to voice port 210 and thence via TD bus to tone detector
circuit 292. Tone detector circuit in voice processor 220 decodes the
dialed digit and transmits a data message to CPU 240 via TD bus, bus
interface 260 and M1 bus. CPU 240 interprets this data message and causes
a voice connection to be established from voice port 210 to a voice
processor 220 where the voice message is converted to digitally encoded
voice signals. These voice signals are transmitted via TD bus, a selected
voice buffer 230, S bus, data base processor interface 290 to data base
processor 113 where the encoded voice is stored for later retrieval.
Handshaking Between Data Base Processor 113 and Voice Buffer 230
A command from the voice storage processor 111 via M1 bus, bus interface
241 and S bus tells data base processor system 113 and voice buffer 230 to
set up a common channel for recording or playback. When the user signals
that he or she is ready to record or play, the voice storage processor 111
is notified and it immediately informs data base processor system 113 and
voice buffer 230 to start the operation.
If the operation is to record a message, data enters voice buffer 230 from
voice processor 220 via TD bus. Voice buffer 220 buffers the data and
delivers it to data base processor system 113 via S bus and data base
processor interface 290.
If the operation is to playback a message, voice buffer 230 interacts with
data base processor system 113 to receive data from data base processor
system 113 through data base processor interface 290 and S bus. Voice
buffer 230 buffers the data and delivers the data to voice processor 220
via TD bus.
This voice mail service system 110 outlined above is a standard
commercially available voice mail service system known as AUDIX that is
available from AT&T Information Systems. The exact operation of this
system is not of paramount importance, but is described in general fashion
to provide a better understanding of the subject integrated message
service system. The data communication segment of this arrangement is now
disclosed to illustrate the apparatus that interconnects system processor
102 with voice mail service system 110 to provide an integrated message
waiting indication.
Data Communication Interface Unit
The Data Communication Interface Unit (DCIU) 103 of telephone switching
system 100 is used to connect the voice storage processor 111 to system
processor 102. Data communication interface unit 103 and other hardware
components, the protocol, and the types of messages on this interface are
described in this section.
Data communication interface unit 103 is necessary for the operation of the
voice mail service system 110. Voice storage processor 111 needs a connect
message to know when to answer one of voice mail service access trunks
104, because it does not act on ringing on the voice mail service access
trunks 104. The connect message also informs voice storage processor 111
if the call is a Voice Mail call or a Call Answer call. The data
communication interface unit 103 is needed for the control of the
automatic message waiting indicators, and the integration of the lamp
message waiting indication feature with other services.
The general structure of data communication interface unit 103 is
illustrated in FIG. 3 in block diagram form. This circuit is a data
transfer arrangement that functions to transmit a message from a main
memory to a communication channel. Such circuits are well-known and U.S.
Pat. No. 4,133,030 issued Jan. 2, 1979 to R. E. Huettner et al describes
one such arrangement. The Huettner et al patent provides a block transfer
arrangement but the concepts taught therein are applicable to the message
transmission arrangement of data communication interface unit 103.
The operation of data communication interface unit 103 is controlled by
processor 301 that is programmed by software stored in memory 302.
Processor 301 responds to message arriving either at interface 303 from
system processor 102 or at message services interface 310-313 from one of
the message service systems by reading the message from the receiving
interface circuit via common bus CBUS. The message is routed by processor
301 to the interface circuit that serves the intended destination. This is
described in further detail below.
Protocol Between Voice Mail Service System 110 and Telephone Switching
System 100
The sections that follow summarize the relevant points of the protocol.
Physical-Layer 1
The data communication interface unit 103 communicates with other devices
through the physical data links. The data communication interface unit 103
has 8 data links for connecting system processor 102 to a maximum of 8
other processors. Also, it can provide a connection between any of the
other processors without involving system processor 102. (See U.S. Pat.
No. 4,488,004 issued Dec. 11, 1984 to F. J. Bogart et al, for additional
details.) Each data link will have a maximum 19.2k bits/s data rate. A DMA
interface circuit 303 is used to connect data communication interface unit
103 to processor 102. However, it is appropriate to regard this DMA
connection as a ninth Data link. In summary, data communication interface
unit 103 will support 9 data links, one of which is a connection to system
processor 102 via DMA interface 303.
The data communication interface unit communication with voice storage
processor 111 is through a Processor Interface Module (PIM) (280-28n),
which is in turn connected to the General Purpose Port (GPP) 291 on the
voice storage processor 111 side. On the voice storage processor 111 side,
the general purpose port 291 is connected to switch communication
processor 270 through the TD bus. General purpose port 291 will provide a
total of 4 physical links. One will be connected to data communication
interface unit 103 via processor interface module 280 and the others will
be available for connections to other devices, via other processor
interface modules. The conceptual view of these data links is that these
are 5 data links; 4 are physical cables that are connected to general
purpose port 291, the fifth data link is the DMA connection across the S
bus to Feature Processor CPU 250.
Data Link-Layer 2 and Packet-Layer 3
Level 2 handles the sending of packets of data over the physical link and
provides flow control, error detection, and error recovery.
Level 3 creates logical channels that are used to multiplex packets over
one data link. Each data link in the data communication interface unit 103
will support 64 logical channels, that can be uniquely identified with the
data link number and logical channel number.
On the system processor 102 side of the interface, data communications
interface unit 103 handles levels 2 and 3 of the protocol. The data link
between system processor 102 and data communication interface unit 103 can
support a maximum of 64 logical channels.
All message transmission through data communication interface unit 103 is
done through a network channel. A network channel is the name for a
connection between 2 logical channels. It is made by mapping a logical
channel data link pair to a logical channel data link. Logical channels
and therefore network channels support bi-directional communication.
Although there are 64 logical channels on each of the links, not all of
these can be used because there is a limit of 128 network channels on each
data communication interface unit 103.
On the feature processor 112 side of the interface, the Data Link-Layer 2
and the Network-Layer 3 is handled by switch communication processor 270.
Switch communication processor 270 is connected to the Time Division (TD)
bus and connected to feature processor CPU 250 by means of S bus, bus
interface 251 and M2 bus. Bus interface 270 provides the layers of
protocol provided by data communication interface unit 103.
Session Layer of the Protocol
The session layers correspond to a subset of the combination of the
following International Standard Organization (ISO) protocol model layers:
the transport layer 4, the session layer 5, and the presentation layer 6.
The session layer is called the level 4, it is concerned with sequencing
of messages and uses level 3 to provide end to end confirmation of
messages. At the boundary between levels 3 and 4, the level 3 logical
channels are mapped, one to one, to ports in level 4. These logical
channels and ports are translated one to one in numerical order.
In system processor 102, each Application program talks to data
communications interface unit 103 via the DCIU Interface Program (DIP).
The DCIU interface program implements the session layer of the protocol,
and DCIU interface program serves as an interface between data
communications interface unit 103 and the system processor application
programs.
In voice storage service system 110, the session layer is handled in the
VMS Interfaces Program (VIP) that resides on feature processor 112. VIP
also communicates with other voice storage processor 111 application
processes and passes information between them and system processor 102.
Application Messages
Data communication interface unit 103 performs a switching function as
outlined above. Both system processor 102 and the various message service
systems 120 can originate messages which are transmitted through data
communication interface unit 103 to a designated destination. The messages
transmitted are discussed below and clarify the routing of the message
through data communication interface unit 103.
The following descriptions of the content of each message are logical
descriptions and not physical formats for implementation. Each message
contains a message opcode followed by the content of the message.
System Processor 102 to Voice Storage Processor 111
CONNECT MESSAGE. When a call is switched to the voice mail service access
trunks 104 connected to voice storage processor 111, the appropriate
information is sent to voice storage processor 111 in a Connect Message.
The voice storage processor 111 voice port to which the call is connected
is identified by using the ringing extension number. The content of the
message is shown below.
Connect--opcode and identification of the message service system.
Ringing Extension--extension number of the port receiving that call.
Call Type--indicates whether calling party is a trunk or a line. If the
call is on a trunk it is `external.` If the call is on a line, it is
`internal.` The opcodes are: (0) means line; (1) means trunk.
Calling Party--is the trunk group number or extension number of the calling
party depending on the Call Type.
Reason for Call--why the call is being sent to VMS. The possible reasons
are:
Direct--VMS is being called directly.
Redirected--The call was redirected to VMS.
Called Extension--is the original extension number being called. This can
be ignored for calls with reasons of type Direct, because it would be the
same as the Ringing Extension or Associated Extension.
Switch Message Waiting Indicator Status--is a bit map of the message
waiting indicator status of the calling extension for each of several
message service systems that use the message waiting indicator. These data
are only present for direct calls.
Thus, the message includes both an opcode and an indication of the
destination to which this message is intended. Processor 301 decodes the
opcode and destination information to determine the one of message service
interfaces (ex. 310) to which the message is routed by processor 301.
Message service interface 310 responds to a message received from
processor 301 over CBUS by transmitting the message to voice mail service
system 110 via data link 105.
The transmitted message is received (as described above) by PIM 280 and
routed through general purpose port 291, ID BUS, switch communication
processor 270, S BUS, bus interface 251, M2 BUS to feature processor CPU
250. Feature processor CPU 250 responds to the received message in
standard fashion to complete the voice connection from telephone station
set T100 to voice mail service system 110 via the selected voice port (ex.
210). A departure from standard operation is that feature processor CPU
250 responds to the switch message waiting indicator data contained in the
received message by retrieving a prerecorded message from the voice store
memory provided by data base processor 113. The prerecorded message is
transmitted in well-known fashion to voice port 210 and thence to the user
at telephone station set T100 via the voice communication connection. The
prerecorded message indicates which message service systems (ex. message
center 120) have stored therein unretrieved messages for the user at
telephone station set T100. Upon the completion of this prerecorded
message, voice mail service system 110 returns to standard operation where
the user can create or retrieve voice mail messages.
DISCONNECT MESSAGES. When the user of VMS goes on hook, system processor
102 notifies voice storage processor 111 the call has terminated.
Disconnect--opcode for disconnect and identification of the message service
system.
Ringing Extension--ringing extension of the port in the call.
SWITCH MESSAGE WAITING INDICATOR STATUS REQUEST MESSAGE. When voice storage
processor 111 requests system processor 102 for the message waiting
indicator status, system processor 102 will respond with this message.
This information will be used by VMS to inform the user of the meaning and
status of the message waiting indicator. This message must exist even
though the Switch message waiting indicator status is sent to voice
storage processor 111 in the Connect Message, because the subscriber may
be calline from off premises or from someone else's extension. Voice
storage processor 111 will discover if this is the case when the
subscriber has logged in, and, if needed, use the Switch Message Waiting
Indicator Status message to retrieve the information.
Message Waiting Indicator Status--opcode and identification of the message
service system.
Extension number--subscriber's extension number
Status for each feature--message waiting indication is on (1), message
waiting indication is off (0). Lamp is off (0).
A bit map shows the indicator status of voice mail, message center,
electronic document communication and leave word calling services.
Voice Storage Processor 111 to System Processor 102
These are the messages that voice storage processor 111 applications send
to system processor 102;
AUTOMATIC MESSAGE WAITING (AMW) INDICATOR MESSAGES. Voice storage processor
111 will send a message to turn on or off the message waiting indicator
status for an ext | | |
