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Description  |
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TECHNICAL FIELD
The invention relates to a voice response unit for use with telephone
networks to recognize a calling customer voice command.
BACKGROUND AND PROBLEM
Telephone networks are used to connect a customer with a voice response
unit associated with a commercial establishment such as a department
store. In operation, a calling customer is connected through a telephone
network to a voice response unit associated with the department store. The
voice response unit responds to a calling customer connection by
transmitting a voice prompt message over the telephone network to the
calling customer. A typical voice prompt message instructs the calling
customer to speak or transmit tones identifying departments available for
customer service. For example, the voice prompt message may inform the
calling customer to speak or transmit a numerical 1 command to be
connected with an order department. The voice prompt message continues to
inform the calling customer that a spoken or transmitted numerical 2, 3, 4
or 5 command operates to connect the customer with billing, appliance,
apparel or customer information departments, respectively. After receiving
the voice prompt message, the calling customer speaks or transmits a
numerical number command identifying a department which the calling
customer has selected.
Voice response units transmit the entire voice prompt message to the
calling customer then waits to receive a customer response. Experienced
customers often do not wait until the end of the voice prompt message but
speak or transmit a command while receiving the voice prompt message. Many
types of customer telephone lines may be connected with a voice response
unit. For example, some customer lines may have short 2-wire telephone
lines while others may have long repeated 2-wire or 4-wire toll telephone
lines. A problem arises in that impedance mismatches arising from the
connection of various types of customer telephone lines with a voice
response unit reflect a part of the voice prompt message transmitted to
the calling customer back to the voice response unit. The reflected part
of the voice prompt message is combined with a customer command
transmitted during the voice prompt message. The combined customer command
and reflected voice prompt message results in a garbled message returned
to the voice response unit. Such garbled messages are not recognized by
the voice response unit. The calling customer must wait until the end of
the transmitted voice prompt message to transmit a responsive command.
SOLUTION
The foregoing problem is solved and voice response units and method of
operating voice response units are substantially enhanced by a voice
response unit having a voice decoder and a voice recorder for generating
voice prompt messages and receiving customer messages and a speech
recognizer for recognizing customer commands transmitted by a customer
while receiving a voice prompt message. Apparatus interconnects the voice
decoder and voice recorder with a telephone line to transmit a generated
voice prompt message and receive a customer message in response thereto
from a calling customer coupled with the telephone line. The apparatus is
also coupled with the speech recognizer for receiving a customer command
combined with a portion of the transmitted voice prompt message reflected
from the telephone line and cancels the reflected voice prompt message
with the transmitted voice prompt message to enable the speech recognizer
to respond to the received customer command and interrupt transmission of
the voice prompt message to start a new transaction with the customer.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a block diagram of a calling customer connected through a
telephone network with a voice response unit embodying the principles of
the instant invention,
FIG. 2 illustrates details of the voice response unit set forth in FIG. 1,
and
FIG. 3 sets forth a method of operating the voice response unit set forth
in FIGS. 1 and 2 in accordance with the principles of the invention.
DETAILED DESCRIPTION
Voice response unit 1, FIG. 1, intended for use at a commercial location,
such as a department store, is connected by telephone line 102 with switch
20 of telephone network 2. Customers of the department store each have a
telephone set 3 connected by telephone line 203 with a switching system of
telephone network 2 such as switches 21 and 20. Switches 20, 21 may be a
type of switch, such as the well-known AT&T No. 1, 1A and No. 5 Electronic
Switching Systems, and need not be described in detail for an
understanding of the invention. Sufficient to say that each switch 20, 21
has equipment, such as network control 202, 212 and line and trunk
equipment 200, 210, 201, 211. Line equipment 200, 210 terminate customer
telephone lines, such as telephone line 103 and 203. Trunk equipment 201,
211 terminate 2-wire telephone trunks 20210, 20211, 20212 and 4-wire
telephone trunks 20213 of telephone network 2. Network control 202, 212
may a program controlled system arranged to control line and trunk
equipment 200, 201, 210, 211 to interconnect customer telephone lines and
telephone network trunks so that customer telephone lines may be connected
with voice response unit 1.
Voice response unit 1 has a voice prompt decoder 11 arranged to receive a
digital prompt message from control 10 and decode the received digital
message into a voice prompt message. Voice recorder 12 records voice
messages received from calling customers located at telephone station 3
and speech recognizer 13 recognizes commands generated by calling
customers in response to voice prompt messages generated by voice prompt
decoder 11. Echo canceller 140 enables speech recognizer 13 to recognize a
calling customer command in the presence of a voice prompt message being
transmitted to a calling customer. Interface unit 15 enables voice
response unit 1 to answer telephone line 102 and control unit 10 controls
the operation of voice response unit 1.
Telephone network 2 in the well-known manner has a large number of
switching systems, such as switches 20, 21. Switching systems are
interconnected by trunks 20210, 20211, 20212 and 20213 and serve to
interconnect calling customer telephone lines 203 with called customer
telephone lines 102. Connections are established by selectively
interconnecting ones of the trunks and ones of the trunks with customer
telephone lines 102, 203 to establish connections between calling and
called customers.
A customer, wishing to place an order with a department store having voice
response unit 1, removes the hand set of telephone set 3. Switch 21
responds to the removal of the hand set by returning dial tone to
telephone set 3. The calling customer dials a telephone number identifying
the department store. Switch 21, upon receiving the telephone number,
enables telephone network 2 to establish a connection via a trunk 20210,
20211, 20212, and 20213 and switch 20 serving voice response unit 1 of the
called department store. Network control 212 of switch 21 establishes a
connection between a selected one of trunks 20210, 20211, 20212 and 20213
and telephone line 203 coupled with telephone station 3. Similarly, switch
20 establishes a connection between the selected trunk 20210, 20211,
20212, 20213 and telephone line 102 connected with voice response unit 1.
Voice response unit interface unit 15 responds to a telephone call incoming
on telephone line 102 by notifying control 10 of the presence of the
incoming call. Control 10 sends a digital voice prompt message to voice
prompt decoder 11 and controls voice prompt decoder 11 to generate a
verbal voice prompt message. The generated voice prompt message is
transmitted over telephone line 102 to switch 20, over the selected trunk
20210, 20211, 20212, 20213 and switch 21 to telephone line 203 and calling
telephone station 3.
Telephone network 2, FIG. 2, has a wide variety of trunks that may be used
to interconnect calling telephone station 3 with voice response unit 1.
The type of trunk used to complete the telephone connection may depend
upon the length of the telephone connection and the type of facilities
used to provide the trunk. For example, a calling customer may be located
nearby the called department store such that telephone network 2 would
interconnect switches 20, 21 with 2-wire trunk 20212, FIG. 2, consisting
of a pair of conductors. The calling customer may be located at a distance
from the called department store that requires that switches 20, 21 be
interconnected by a 2-wire trunk 20210 having loading coils 202100 that
function to improve the gain characteristics of the trunk. In yet another
application, switches 20, 21 may be interconnected by a 2-wire trunk 20211
having a 2-way repeater 202110 with gain characteristics that enables the
calling customer to be coupled with voice response unit 1. Switches 20,
21, FIG. 1, may also be interconnected by 2-wire-4-wire trunk 20213 which
has 4-wire term sets 202130, FIG. 2, at each end of trunk 20213 to
interconnect a 2-wire telephone line 102, 103 with the 4-trunk facilities.
Trunk 4-wire facilities may be represented as having directional gain
devices 202131 in each 2-wire leg to improve the overall gain
characteristics of 4-wire trunk 20213.
Voice response unit apparatus 14 has universal and bidirectional
transmission ports for use in interconnecting apparatus with telephone
line 102. For example, a receiving unidirectional transmission port is
coupled with voice prompt decoder 11 to receive a voice prompt message
generated by voice prompt unit 11 for transmission to a calling customer.
A first transmitting unidirectional transmitting port is coupled with
voice recorder 12 so that voice reorder 12 may receive verbal telephone
messages generated by calling customers. A second transmitting
unidirectional transmitting port is coupled with speech recognizer 13 in
order that speech recognizer 13 may receive verbal commands from the
calling customer in response to the transmitted voice prompt message.
Unidirectional transmission ports are interconnected with 4-wire term set
141 which in turn is coupled with a bidirectional transmission port
coupled with telephone line 102. Thus, voice prompt decoder 11 and voice
recorder 12 are connected via the unidirectional and bidirectional
transmission ports and 4-wire term set 141 with interface unit 15 and
telephone line 102.
The 4-wire term set 141 has impedance matching apparatus 142 which
functions to match the combined impedances of telephone line 102 and
telephone network trunks 20210, 20211, 20212, 20213 that are selectively
interconnected with telephone line 102. When impedance matching apparatus
142 matches the combined impedances of telephone line 102 and a trunk
coupled therewith, all of a voice prompt message generated by voice prompt
decoder is transmitted over telephone line 102 to calling telephone set 3.
If a mismatch of impedances occurs, such as a condition whereby impedance
apparatus 142 does not match the combined impedance of telephone line 102
and an interconnected telephone network trunk, a portion of the
transmitted voice prompt message is reflected back from telephone line 102
to voice recorder 12 and echo canceller 140.
Echo canceller 140 is interconnected with the unidirectional ports coupled
with voice prompt decoder 11 and with voice recorder 12. In addition, echo
canceller 140 is coupled via a unidirectional transmission port of
apparatus 14 with speech recognizer 13. A voice prompt message transmitted
by voice prompt decoder 11 is applied to a filter 1400. The output of
filter 1400 is coupled with one input of math unit 1401 which has another
input coupled with the unidirectional transmission port connected with
voice recorder 12. Math unit 1401 operates to subtract a voice prompt
message generated by voice prompt decoder 11 from a message received on
telephone line 102 which may be combined with a portion of the transmitted
voice prompt message that is reflected by a mismatch of impedance
apparatus 142 with the combined impedances of telephone line 102 and a
telephone network trunk. The message received from calling telephone set
3, FIG. 1, from which the reflected portion of the transmitted voice
prompt message has been cancelled by echo canceller 140, FIG. 2, is
transmitted via a unidirectional port of apparatus 14 to speech recognizer
13.
In operation, FIG. 1, a calling customer wanting to place an order with a
department store removes the hand set of telephone set 3 and dials the
telephone number of the department store. Network control 212 of telephone
network switch 21 responds to the dialed number by enabling line and trunk
links 210, 211 to establishing a voice connection from telephone line 203,
via a selected one of the telephone trunks 20210, 20211, 20212 or 20213,
with switch 20. Network control 202 of switch 20 controls trunk and line
links 201, 200 to establish a connection from a selected trunk 20210,
20211, 20212, 20213 with telephone line 102 connected with voice response
unit 1.
Voice response unit 1, FIG. 3, initially in an idle state, step 40,
receives the incoming call from telephone set 3, step 41. The incoming
call, step 41, is answered, step 42, by interface unit 15, FIG. 2.
Interface unit 15 notifies voice response unit control 10 of the presence
of the incoming call via bus 16. Control 10 starts a customer transaction,
FIG. 3, step 43, by sending a digital voice prompt message over bus 16,
FIG. 2, to voice prompt decoder 11. Voice prompt decoder 11 transmits the
generated voice prompt message via a unidirectional transmission port to
4-wire term set 141. The 4-wire term set 141 transmits the voice prompt
over telephone line 102 through switches 20, 21 and the selected trunk
20210, 20211, 20212 or 20213 and telephone line 203 to telephone set 3.
The voice prompt message instructs the calling customer to speak a command
or transmit command tones identifying departments available for customer
service. For example, the voice prompt message may inform the calling
customer to speak or transmit a command comprising a numerical 1 if the
calling customer desired to be connected with an order department. The
voice prompt message continues to inform the calling customer that a
spoken or transmitted numerical command of 2, 3, 4 and 5 will operate to
connect the customer with billing, appliance, apparel or customer
information departments, respectively.
When a call connection has been established with voice response unit 1,
FIG. 2, a mismatch of impedance apparatus 142, with the combined
impedances of telephone line 102 interconnected with a trunk of telephone
network 2, results in a portion of the transmitted voice prompt message
being reflected and returned to voice recorder 12 and echo canceller 140.
Each voice prompt message transmitted to a calling telephone set 3 by
voice prompt decoder 11 is applied to echo canceller filter 1400 connected
with the unidirectional transmission port coupled with voice prompt
decoder 11 for the purpose of filtering the voice prompt message
transmitted to calling telephone set 3. Math unit 1401, having inputs
connected with filter apparatus 1400 and 4-wire term set 141 and an output
connected with speech recognizer 13, subtracts the filtered voice prompt
message from the voice prompt message reflected from 4-wire term set 141
to cancel the reflected voice prompt message.
The calling customer may, while receiving a first portion of the voice
prompt message at telephone set 3, FIG. 1, verbally speak a numerical 1
command into the hand set of telephone set 3 indicating that the customer
would like to place an order with the order department of the department
store. The customer spoken numerical 1 command is received over the
telephone network selected trunk and telephone line 102 at voice response
unit 1. Since the voice prompt message is still being transmitted by voice
prompt decoder 11, the received customer numerical 1 command is combined
with the portion of the transmitted voice prompt message reflected from
telephone line 102. The resulting combined message is transmitted by
4-wire term set 141, FIG. 2, to an input of echo canceller math unit 1401.
Math unit 1401, receiving the transmitted voice prompt message, functions
to cancel the reflected voice prompt message from the combined voice
prompt message and customer numerical 1 command by subtracting the
transmitted voice prompt message from the combined message appearing at
the input of math unit 1401 from 4-wire term set 141. The resulting
customer numerical 1 command is applied, via a unidirectional transmission
port of apparatus 14, to speech recognizer 13. Speech recognizer 13
responds to receipt of the received numerical 1 command by sending the
received calling customer command to control 10. Control 10 responds to
the received command and overrides the transmitted voice prompt message by
controlling voice prompt decoder 11 to interrupt transmission of the voice
prompt message and end the current transaction with the calling customer.
Following interruption of the transaction, voice response unit 1, under
control of control 10, initiates procedures to record order information of
the calling customer.
In the method of operation, FIG. 3, the voice response unit is in an
initial idle state, step 40. Upon receiving an incoming calling customer
call, step 41, voice response unit 1 answers the customer call, step 42,
and starts a first transaction, step 43, by transmitting a voice prompt
message to the calling customer and prepares to receive customer messages.
Echo canceller 140, FIG. 1, starts to cancel the portion of the
transmitted voice prompt message generated by voice prompt decoder 11 from
the portion of the voice prompt message reflected from 4-wire term set
141, FIG. 3, steps 44, 45. A customer command, received and recognized by
the voice prompt decoder 11, step 46, enables voice response unit 1 to
override the transmitted voice prompt message by controlling voice prompt
decoder 11 via control 10, FIG. 2, to interrupt transmission of the voice
prompt message by stopping transmission thereof, FIG. 3, step 47. If other
transactions are required, step 48, steps 43 through 48 are repeated until
all transactions are completed at which time voice response unit 1 returns
to the idle state, step 40. If speech recognizer 13 does not recognize the
customer command, step 46, the voice prompt message continues to be sent
to the calling customer.
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Description |
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