PBX transparent ANI and DNIS using VRU

Method and apparatus to enable a PBX or CBX to receive ANI and DNIS information and to provide this information to customer business applications. One embodiment discloses a trunk adapter 20 that includes an ISDN primary or basic interface 20A that receives ANI and/or DNIS information from a network provider's switch. The trunk adapter, in response to answer supervision, employs DTMF signals to outpulse this information, via a novel protocol, over a T1 interface, through a PBX 14 to a VRU 14A. The VRU 14A subsequently provides the ANI and/or DNIS information to a Host data processor 12. The PBX 14 is essentially "transparent" to the DTMF tones that are used to convey the ANI and DNIS information from the trunk adapter 20 to the VRU 14A. In another embodiment the network provider's switch directly provides the ANI and/or DNIS information via DTMF in accordance with the novel protocol. The protocol comprises DTMF digits having the format "* ANI * DNIS * ", where both ANI and DNIS are digits corresponding to the billing number of the call and the number dialed, respectively, and the first phoneset star "*" digit signals the beginning of the DTMF packet of information, the second separates the ANI data filed from the DNIS data field, and the third terminates the packet of information.

FIELD OF THE INVENTION 
This invention relates generally to telephony equipment and, in particular, 
to method and apparatus for providing collection of ANI and DNIS 
information directly by a VRU through a PBX that supports ring-down of 
call connections from a network and return of answer supervision to the 
network upon VRU answer. 
BACKGROUND OF THE INVENTION 
Several protocols are known to exist for passing a caller's phone number 
and the called phone number between a customer's Private Branch Exchange 
(PBX) and a phone network. By example, one network provider offers 
Integrated Services Digital Network (ISDN) in-band ANI services that 
provide combinations of Automatic Number Identification (ANI), that is the 
caller's billing number, and Dialed Number Identification Service (DNIS) 
providing up to the last seven digits of the called number. The ANI and 
DNIS information is provided in-band to PBXes in order to identify the 
caller and to identify what services were dialed by the caller. However, 
to use this protocol for in-band ANI and/or DNIS PBX vendors are required 
to create interfaces for the protocol such that PBXes may employ this 
information to provide routing, queuing priority, and intelligent 
answering capabilities. One problem in creating such an interface relates 
to a requirement that existing PBXes be modified, such as by providing new 
software, in order to collect the ANI and DNIS information. Such 
modifications are generally undesirable both from a customer's and a 
vendor's viewpoint. 
It is thus one object of the invention to provide a novel protocol that 
requires only network protocol changes in order to enable existing PBXes 
to receive ANI and DNIS and provide this valuable information to customer 
business applications. 
It is another object of the invention to provide method and apparatus that, 
in response to an incoming call, returns a call accepted signal to a 
network and transmits DTMF-encoded ANI and/or DNIS signals over a T1 trunk 
group to and through a PBX, the transmitted information being expressive 
of ANI and/or DNIS information. 
SUMMARY OF THE INVENTION 
The foregoing problems are overcome and the objects of the invention are 
realized by a method of providing ANI and/or DNIS information to a user of 
a network. The method includes a step of transmitting a packet of 
information using DTMF signals in accordance with a predetermined protocol 
having a format "* ANI * DNIS * " wherein ANI and DNIS each comprise 
digits corresponding to the billing number of the call and the number 
dialed, respectively. The first phoneset "*" digit indicates the beginning 
of the packet of information, the second phoneset "*" digit separates the 
ANI digits from the DNIS digits, and the third phoneset "*" digit 
terminates the packet of information. 
The invention also teaches method and apparatus for providing ANI and/or 
DNIS information from a network provider's switch to a network provider's 
user or customer site. In response to an incoming call there is returned 
to the network a signal indicating that the incoming call has been 
accepted at the network provider's customer site. Responsive to the 
receipt of this signal there is transmitted information with DTMF signals 
to and through the customer's local branch exchange. The information is 
expressive of ANI and/or DNIS information and is transmitted in accordance 
with the format described above. The information is received at the 
customer site and may be employed to affect further call processing, such 
as to identify a destination phone number or call answering resource to 
which to direct the call.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION 
FIG. 1 illustrates in block diagram form a telephony system, in particular 
a Call Management Control System (CMCS) 10 that includes the teachings of 
the invention. System 10 in a presently preferred embodiment of the 
invention includes a host processor (Host) 12 that may be coupled via a 
Logical Unit (LU) 6.2 interface to a local branch exchange such as a 
Private Branch Exchange (PBX) 14. The local branch exchange may also be a 
Computerized Branch Exchange (CBX). The Host 12 includes a MEMORY 12A that 
is comprised of both temporary RAM and a mass storage device such as a 
magnetic disk or magnetic tape unit. Particularly suitable apparatus that 
embodies these functional blocks is described in detail in commonly 
assigned U.S. Pat. No. 4,805,209, issued Feb. 14, 1989. The disclosure of 
U.S. Pat. No. 4,805,209 is incorporated by reference herein in its 
entirety. Although the ensuing description is made in reference to a 
hardware and software system as described in U.S. Pat. No. 4,805,209 it 
should be realized that the teaching of the invention is not limited for 
use with only such a system and that, instead, the teaching of the 
invention is applicable to a large number of possible hardware and/or 
software embodiments. 
The Host 12 may be a type of IBM System/370 processor, a description of 
which is found in a document entitled "S/370 Reference Summary, 
GX20-1850", published by the International Business Machines Corporation. 
While the Host 12 in a presently preferred embodiment of the invention is 
embodied in a S/370 processor it should be realized that the invention can 
be practiced with other mainframes, minicomputers or microprocessors. 
The PBX 14 may be a PBX known in the art as a ROLM 8000 or a ROLM CBX II 
9000, a description of which is found in a document entitled "ROLM CBX II 
9000 Business Communications System", published by the ROLM Corporation 
(1986). It should be realized, however, that the invention can be 
practiced with other varieties of PBX or CBX equipment and, in general, 
with any PBX that supports ring-down of call connections from a network 
and which returns answer supervision to the network upon answer. 
The LU 6.2 communication link between the Host 12 and the PBX 14 is a 
standard System Data Link Control (SDLC) communication link that 
corresponds to the LU 6.2 standard. A detailed description of a LU 6.2 
communication link and a description of how to implement a program 
interface to conform with this standard is provided in the following 
documents published by the International Business Machines Corporation: 
"Systems Network Architecture: Sessions Between Logical Units, GC20-1868" 
and "SNA Transaction Programmer's Reference Manual For LU 6.2, GC30-3084". 
In other embodiments of the invention the link between the Host 12 and the 
PBX 14 may be other than a communication link that conforms to the LU 6.2 
standard. In still other embodiments of the invention this link between 
the Host 12 and the PBX 14 is not required, the Host 12 instead being 
coupled to the PBX 14 through a Voice Response Unit as will be described. 
As described in U.S. Pat. No. 4,805,209 there are coupled to Host 12 a 
plurality of user interface terminals, shown herein as terminals 16 (TERM 
1 through TERM m). Coupled to PBX 14 are a plurality of phones, shown 
herein as phones 18 (PHONE 1 through PHONE n). 
A Voice Response Unit (VRU) 14A, such as a type known in the art as an IBM 
9270, is coupled between the PBX 14 and the Host 12. VRUs, such as the IBM 
9270, may be employed to ring down callers to equipment that permits 
direct caller phone access to Host 12 data by using Dual Tone Multiple 
Frequency (DTMF) input with voice responses. The VRU 14A may subsequently 
employ PBX 14 features such as call transfer in order to transfer a caller 
to an agent if further assistance is required. 
In accordance with a first embodiment of the invention there is also 
coupled to PBX 14, via a T1 tie link, a trunk adapter 20 that interfaces 
the PBX 14 to an ISDN phone trunk. The trunk adapter 20 may be a type 
known in the art as an IBM 9757. The phone trunk couples the PBX 14 to the 
network provider's switch (not shown) that generates the ANI and DNIS 
information. 
In accordance with this embodiment of the invention the trunk adapter 20 
includes an ISDN primary or basic interface 20A that receives ANI and/or 
DNIS information from the network provider's switch. The format of this 
information is in accordance with ISDN D Channel Signalling as defined by 
CCITT Standards Vol. III (ISDN 92-61-02081-X). The information is buffered 
(BUFF 20B) by the trunk adapter 20 and subsequently outpulsed as DTMF 
signals. The outpulsing of the ANI and/or DNIS information is delayed 
until after answer supervision is received from the PBX 14. The outpulsed 
information is transmitted in accordance with the protocol of the 
invention over an immediate start T1 tie through the PBX 14 and to the VRU 
14A. The VRU 14A subsequently provides the ANI and/or DNIS information to 
the Host 12. As such, no modification of the PBX 14 is required in that 
the PBX 14 is essentially "transparent" to the DTMF tones that are used to 
convey the ANI and DNIS information from the trunk adapter 20 to the VRU 
14A. In a presently preferred embodiment of the invention each DTMF tone 
has a duration of 80 milliseconds and is separated from other tones by 
intervals of 80 milliseconds. 
In accordance with a second embodiment of the invention the network 
provider's switch employes a T1 trunk and DTMF tones in conjunction with 
the novel protocol of the invention to provide the ANI and DNIS 
information in response to receipt of the answer supervision signal. This 
information passes though the PBX 14 to the VRU 14A. In the second 
embodiment the functionality of the trunk adapter 20 may be considered to 
have been moved "upstream" and incorporated within the network provider's 
switch. 
As such, the invention provides a novel protocol that allows ANI and DNIS 
capabilities to be exploited using any PBX, the use of the invention not 
requiring changes to an existing PBX interface. The protocol on the PBX 14 
side of the connection is a standard trunk interface with ring-down to a 
single or a plurality of VRUs 14A. On the network side of the connection, 
protocol changes are made. The two embodiments of the invention relate to 
the network side of the PBX 14. A first embodiment uses the trunk adapter 
20 to interface the PBX with standard E&M T1 while a second embodiment 
requires that the network provider switch implement the novel protocol. 
As is shown in the flowchart of FIG. 2 an embodiment of the invention 
provides that the PBX 14 network interface, for example trunk adapter 20, 
outpulse previously received and buffered ANI and/or DNIS information 
after receiving answer supervision from the PBX 14. Thus, the PBX 14 
routes a call to the VRU 14A using existing capabilities. That is, in 
response to call request from the network (block 30) a line is seized and 
the PBX 14 rings down to the VRU 14A (block 32). Upon the VRU 14A 
answering the call (block 34) the PBX 14 sends answer supervision (block 
36) towards the network over the T1 line to indicate that the call has 
been accepted and that billing may begin. The trunk adapter 20 receives 
the answer supervision and the call path is cut through the PBX 14 
connecting the VRU 14A to the trunk adapter 20 (block 38). The trunk 
adapter 20 outpulses ANI and/or DNIS information previously received from 
the network switch employing DTMF encoded digits having the format" * ANI 
* DNIS * " (block 40). The ANI and/or DNIS information is provided to the 
VRU 14A transparently through the PBX 14. The VRU 14A collects the ANI and 
DNIS information and sends it to the Host 12 where it is available to any 
application that may require the information for further call processing, 
as described below. At block 42 the trunk adapter 20 sends delayed answer 
supervision to the network switch and at block 42 the connection is made 
between the network provider's switch and the VRU 14A. 
As examples of further call processing made possible by the use of the 
invention the Host 12 application may apply the ANI and the DNIS 
information against a customer business database to determine a phone 
number to send the caller to. The phone number chosen can be used to 
select an appropriate service group for the caller, may determine the 
caller's priority in a queue of calls waiting for service, or may display 
information on the identity of the caller. Alternatively, the VRU 14A that 
transfers the caller to the target phone number may stay on the call until 
the target agent answers at which time the VRU 14A speaks the caller's 
identification to the agent before hanging up. A determination that the 
agent has answered can be by a number of methods including having the 
agent enter a DTMF prompt to the VRU 14A, such as by hitting a 
predetermined key on the agents phone 18, or by using tone detection to 
detect the agent's voice when answering the call. In accordance with the 
disclosure of the aforementioned U.S. Pat. No. 4,805,209 the caller 
associated screen appearing on a VRU 14A terminal can also be made to 
display on the receiving agent's terminal 16 to identify the caller to the 
agent. 
As was previously stated, upon the VRU 14A answering an incoming call the 
PBX 14 sends answer supervision towards the network and the call path is 
cut through the PBX 14 connecting the VRU 14A to the PBX 14. The network 
interface at this time outpulses DTMF digits having the format "* ANI * 
DNIS * " to the VRU 14A transparently through the PBX 14. Both ANI and 
DNIS are digits corresponding to the billing number of the call and the 
number dialed, respectively. Furthermore, if only ANI is provided by the 
network interface the ANI information is transmitted as "* ANI * *". If 
only DNIS is provided the format is "* * DNIS *. If neither type of 
information is available the format is "* * * ". In any event three 
phoneset star "*" digits are transmitted in accordance with the protocol 
of the invention, the first signalling to the VRU 14A the beginning of the 
DTMF packet of information, the second separating the ANI data field from 
the DNIS data field, and the third terminating the packet of information. 
As such, the invention accommodates variable numbers of digits in each of 
the fields. 
The VRU 14A locally buffers the ANI and DNIS information and provides same 
to the Host 12. However, situations of overload may arise, such as having 
to place the incoming call into a queue, where the PBX 14 discards the ANI 
and DNIS information by sending answer supervision without connection to a 
VRU. In this case the network outpulses ANI and DNIS to the PBX which 
ignores the information. 
The method and apparatus of the invention advantageously extends the 
collection of ANI and DNIS information directly by a VRU through any PBX 
that supports ring-down of call connections from a network and which 
returns answer supervision to the network upon VRU answer. The invention 
provides for ANI and DNIS information to be passed to Host 12 business 
applications, such as Host 12 directed call routing based on the identity 
of a caller and what service the caller has requested. 
Thus, while the invention has been particularly shown and described with 
respect to a preferred embodiment thereof, it will be understood by those 
skilled in the art that changes in form and details may be made therein 
without departing from the scope and spirit of the invention.