System and method for alternate billing arrangement during a telephone call

A system and method for effecting alternate billing arrangements after a call from a calling party to a called party has been completed. Signaling information identifying an alternate billing request from a called party is first captured. The alternate billing request is then validated by determining whether it is permissible to shift all or part of the charges for the call to the called party.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to telecommunications systems, and 
more specifically is directed toward systems and methods for effecting 
alternate billing arrangements. 
2. Related Art 
Telephone calls connecting distant subscribers are typically charged on a 
per-use basis. These charges typically accrue at a rate (e.g., per-minute 
charge) that is dependent upon the amount of network facilities that are 
being used over the path of the telephone call. Thus, a telephone call 
originating in New York and terminating in Seattle can justify a higher 
facility charge as compared to a telephone call originating in New York 
and terminating in New Jersey. This results since the New York-Seattle 
telephone call will traverse an entirely different transport path which 
includes additional switches, fiber-optic transport equipment, etc. Note 
that this scenario represents a simple example of how an inter-exchange 
carrier (IXC) can implement a form of price differentiation within their 
billing scheme. Note further that a similar scenario also exists within 
the local exchange carriers (LECs) as they connect subscribers that reside 
within various LATAs. 
In addition to the price differentiation that is loosely tied to the 
physical distance between the calling and called parties, IXCs and LECs 
can also augment the standard connection charges based upon the types of 
services provided. For example, if a calling party desires to make a 
calling card call, then additional services are required. These additional 
services include database queries and validation procedures. Like the 
actual switching and transport facilities for the voice channel, the 
database and validation procedures represent valuable network resources 
that are being used by the calling party. The calling party can then be 
charged accordingly by increasing the per-minute charge of the calling 
card call. 
As these examples illustrate, the billing of a telephone call is typically 
applied to the calling party. There are many instances, however, where the 
calling party desires to shift the billing of the telephone call to the 
called party. For example, a college student may desire to call his or her 
parents at home with the parents picking up the bill for the call. In 
other examples, a calling party at a pay phone may desire to place a long 
distance call without having enough coins to continually insert into the 
pay phone. In these types of scenarios, the calling party can simply 
decide to place a collect call. Collect calls typically require the 
provision of an operator to facilitate the call setup process. In this 
process, the operator or a computerized system intervenes to determine 
whether the called party is willing to accept the charges of the collect 
call. In a similar manner to calling card calls, the provision of an 
operator or computerized system to the collect call represents a valuable 
network resource that is being used by the calling party. The usage of 
additional resources allows an IXC or LEC to justify a higher per minute 
usage charge for the collect call. 
To avoid these premium charges for collect calls, calling parties have 
resorted to other methods to shift the billing burden onto the called 
party. In one example, the calling party can place a first call to the 
called party, hang up, and wait for the called party to place a second 
call back to the original calling party. In another example, the calling 
party can place a collect call to the called party who will refuse the 
charges then subsequently place a call to the original calling party. 
Numerous variations to this theme exist. 
While the bill-shifting techniques described above are useful to varying 
degrees, they each require that a particular procedure be followed prior 
to a call. These procedures are often inflexible in requiring that a 
decision be made in advance to have the charges revert to the called 
party. What is therefore needed is a more flexible alternative that allows 
the calling and called parties to decide how to shift the billing burden. 
SUMMARY OF THE INVENTION 
The present invention satisfies the above mentioned needs by providing a 
system and method for effecting alternate billing arrangements during a 
switched bandwidth connection (e.g., a telephone call). After a connection 
is established from a calling party to a called party, the called party is 
given the opportunity to alter the billing arrangement. In conventional 
systems, the cost of the connection is levied solely on the calling party. 
In the present invention, the called party can shift to himself all or 
part of the cost of the connection that was originated by the calling 
party. 
In implementation, the alternate billing system comprises a means for 
identifying signaling information (in-band or out-of-band) from the called 
party. This signaling information identifies the called party's 
willingness to accept all or part of the cost of the call. In one 
embodiment, the identifying means is embodied as a dual-tone 
multi-frequency (DTMF) detector. This DTMF detector is situated on the 
unidirectional part of the provisioned channel that is dedicated to 
transmission from the called party. This DTMF detector monitors the 
connection during its entire duration to determine whether the called 
party has generated a predefined sequence of one or more tones. This 
predefined sequence of tones identifies an alternate billing request by 
the called party. In other embodiments dedicated to integrated services 
digital network (ISDN) connections, the signaling information is 
identified through the monitoring of the D channel in the ISDN basic rate 
interface. 
After an alternate billing request is identified, it is then determined 
whether the alternate billing request is permitted. Examples of alternate 
billing requests that are denied include situations where the called party 
is situated at a pay phone, the called party has a poor credit history, 
etc. If the alternate billing request is approved, the system informs the 
billing system of the new billing arrangement. 
The foregoing and other features and advantages of the invention will be 
apparent from the following, more particular description of a preferred 
embodiment of the invention, as illustrated in the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 illustrates an exemplary long-distance connection in a public 
switched telephone network (PSTN) 100. PSTN 100 includes both 
interexchange carriers (IXCs) and local exchange carriers (LECs). 
Individual subscribers 101-106 are connected to a LEC via an LEC end 
office (EO). As illustrated, subscribers 101-103 are connected to EO 112 
and subscribers 104-106 are connected to EO 114. An LEC EO 112, 114 
generally includes switching equipment to complete calls among individual 
subscribers. 
Connections 142 from subscribers 101-106 to one of EOs 112, 114 are 
typically provided at least in part by a twisted pair of copper wires. 
Connections between individual subscribers 101-106 residing in distant 
locations are typically provided by both an LEC and an IXC. Consider a 
telephone call connection between subscriber 101 and subscriber 106. In 
this connection, a telephone call would traverse a path that included EO 
112, IXC switch (SW) 122, IXC SW 124, IXC SW 126 and EO 114. 
To initiate this telephone call, subscriber 101 dials the number of the 
desired destination. The dialed digits are collected and analyzed in 
conjunction with information about the calling station by data processing 
equipment (not shown) within EO 112. Upon recognition that the dialed 
number is not a local destination, EO 112 directs the telephone call to 
IXC SW 122 through a trunk line 144. Routing of the telephone call through 
the LEC and IXC switches is coordinated through a common channel signaling 
(CCS) network 132 that uses a protocol such as Signaling System #7 (SS7). 
Communication with CCS network 132 is provided via signaling links 
151-155. CCS network 132 may access a database (DB) 134 to look up routing 
information or subscriber-specific data. 
FIG. 2 illustrates a more detailed view of the connection of FIG. 1 that 
further includes both billing and tone detecting elements. The 
illustration is provided for an exemplary connection between subscribers 
101 and 106. As noted above, subscriber 101 is connected to EO 112 by a 
twisted pair of copper wires 142. This twisted pair of wires 142 carries 
both directions of the conversation between subscribers 101 and 106. The 
two-way transmission on twisted pair 142 is facilitated by hybrids within 
the telephone of subscriber 101 and at EO 112. For simplicity, only hybrid 
202 within EO 112 is shown. 
A hybrid is a special directional circuit that distinguishes between 
incoming and outgoing signals. A hybrid within the telephone of calling 
party 101 can induce a current in twisted pair 142 as calling party 101 
speaks into the mouthpiece of the telephone. The hybrid can also detect 
currents caused by called party 106 and provides an audio signal to the 
telephone earpiece of subscriber 101. Generally, a hybrid is used so that 
a given telephone does not receive its own outgoing signals. 
In EO 112, twisted pair 142 is coupled to hybrid 202 to separate the 
subscriber loop signal into two unidirectional signals. These 
unidirectional signals are individually switched, amplified, digitized, 
and transmitted in PSTN 100. As further illustrated in FIG. 2, EO 112 also 
includes switching matrix 211 that dynamically connects subscriber 101 
either to another attached subscriber 102, 103 or to another switch via a 
trunk. In the exemplary connection between subscribers 101 and 106, the 
unidirectional signal in the direction of subscriber 106 passes through 
IXC switches 212-214 in succession. At EO 114, switch matrix 215 completes 
the call through hybrid 204 to subscriber 106. Generally, each of switches 
211-215 contains a controller (not shown) such as a small programmable 
computer, that controls the switching matrix and communicates with CCS 
network 132 via signaling links 151-155. 
As further illustrated in FIG. 2, EO 112 further includes dual tone 
multi-frequency (DTMF) detector 222. DTMF detector 222 recognizes digits 
dialed from a touch tone phone of calling party 101. In typical telephone 
calls, DTMF detector 222 is engaged only during call initiation. As 
illustrated, DTMF detector 222 is connected to the unidirectional signal 
that is transmitted in the direction of called party 106. In this manner, 
DTMF detector 222 is able to recognize the digits dialed by calling party 
101. These captured digits are provided to the controller (not shown) of 
switch matrix 211 to identify called party 106. When an adequate number of 
digits are provided, the controller can decide how to route or terminate 
the call. 
After the call is completed from calling party 101 to called party 106 
record collecting processes (RCPs) operating in one or more switches in 
the path of the call are started. In FIG. 2 each switch 211-215 starts a 
respective RCP 231-235, respectively. The resulting raw call detail 
records (CDRs) from each switch 211-215 are collected and fed into call 
record and billing processors 240. Call record and billing processors 240 
derives billing information from raw CDRs. In this process, CDRs are 
grouped as relating to a single telephone call, discrepant or redundant 
CDRs are resolved, and the origin, destination, duration and applicable 
rate for each call are determined. The charges for calling party 101 are 
then tabulated. 
As noted above, the conventional call setup and billing process is designed 
to attribute the entire charge for network usage to the calling party. 
Shifting of any charges incurred for the telephone call can be 
accomplished through collect calling and manual callback processes. Each 
of these alternatives has proven inflexible to meet the needs of 
individual subscribers. 
FIG. 3 illustrates a preferred embodiment of the present invention that 
allows a calling and called party to dynamically apportion the billing 
burden during the telephone call. As shown, an additional DTMF detector 
302 is placed on unidirectional link 312. Unidirectional link 312 is one 
link in the unidirectional path in the direction of calling party 101. 
DTMF detector 302 is designed exclusively to capture touch tone digits 
that are generated by the called party after the telephone call has been 
completed. Briefly, the touch tone digits generated by called party 106 
determine how much of the billing burden should be shifted from calling 
party 101 to called party 106. In conventional systems, dialing signals 
from a called party typically held no significance. 
Note that the illustration of FIG. 3 places DTMF detector 302 at the 
interface between LEC EO 114 and IXC switch 126. This choice is largely 
one of convenience for description purposes. In the exemplary connection, 
the billing function for the long-distance telephone call is being 
provided by the IXC. In the simplest scenario, the IXC itself collects the 
digits from called party 106. Link 312 represents the first opportunity 
that the IXC could directly collect the touch tone digits generated by 
calling party 106. As will become apparent from the following description, 
DTMF detector 302 could be placed on any of unidirectional links 311-316 
in the unidirectional path. 
In operation, DTMF detector 302 remains on-line throughout the duration of 
the telephone call from calling party 101 to called party 106. As noted 
above, conventional systems utilized DTMF detector 222 only during a short 
digit collection timeframe prior to completion of a telephone call to 
capture input from a calling party only. 
FIG. 4 illustrates a flow chart of the processing of a telephone call 
including the bill-shifting function provided by the operation of DTMF 
detector 302. The process begins at step 402 where calling party 101 goes 
off-hook and dials the number of called party 106. As noted above, the 
number of called party 106 is captured by DTMF detector 222 during the 
call setup phase of the call. After the controller in matrix switch 112 
receives the dialed digits, a connection is established to called party 
106 at step 404. Specifically, at step 404, a voice grade channel is 
provisioned across switches 112, 122, 124, 126 and 114 using signaling 
network 132. Once the voice grade channel is provisioned, matrix switch 
114 causes the called party's telephone to ring. If called party 106 
answers, a connection is then established. 
The completion of the connection is represented by step 406. At this point 
in time, a conversation between calling party 101 and called party 106 
ensues. During this conversation, controllers within the switches will 
continue to determine at step 408 when either party 101 or 106 hangs up 
(i.e., on hook) signaling the end of the telephone call. If a controller 
determines at step 408 that the telephone call is completed, the 
connection between calling party 101 and called party 106 is taken down at 
step 410. 
In addition to determining when an on-hook condition is detected, one or 
more controllers also determine at step 412 whether an alternate billing 
request is received. In one embodiment, an alternate billing request is 
signaled based upon the receipt of touch tone digits by DTMF detector 302. 
Note again that DTMF detector 302 can be located at any point along the 
unidirectional path in the direction of calling party 101. DTMF detector 
302 can be dedicated exclusively to the collection of alternate-billing 
requests by the called party. Any predefined sequence of digits can be 
used to designate the amount of the bill (e.g., 100%, 75%, 50%, etc.) that 
will be shifted to the called party. For example, a controller that 
receives digits from DTMF detector 302 may determine that the telephone 
call should be billed entirely to the called party based upon the receipt 
of "##". Alternatively, the controller can shift a percentage of the cost 
of the call to the called party based upon the receipt of "#X", where X 
represents the % of the bill to shift. 
Generally, if no alternate billing request is detected at step 412, the 
telephone call processing continues in a standard fashion. If, however, a 
controller determines that an alternate billing request has been received 
at step 412, then a validation step is performed at step 414. This 
validation step determines whether it is permissible to shift the cost of 
the call to the called party. This determination can depend on the type of 
phone or class of service at either end, subscriber account history, 
subscriber preferences, etc. 
For example, consider the case where called party 106 is on a pay phone. If 
this is the case, shifting of the billing to called party 106 is 
completely impermissible due to the unlikelihood that called party 106 
would pay for the call. A similar result would also be reached if it is 
determined that called party 106 has a history of credit problems. 
Information on customers and their respective preferences can be stored in 
database 134 that is accessible by signaling network 132. 
If the controller determines that the alternate billing request is not 
permitted, the calling and called parties are informed at step 416. The 
processing of the telephone call then proceeds normally until termination. 
If, however, at step 416, the controller determines that the alternate 
billing request is permitted, then the controller changes the applicable 
CDRs that it generates. The modified CDR would then indicate that a 
percentage of the cost of the call should be billed to the called party. 
Alternatively, the controller could simply communicate or record the need 
to modify the CDR at a later point in time (step 418). Once the CDR has 
been modified or a need to modify a CDR has been noted, the parties are 
notified of the acceptable alternate billing arrangement at step 420. 
Thereafter, the processing of the telephone call continues normally until 
termination. 
FIG. 5 illustrates an alternative method of implementing an alternate 
billing system in the context of an integrated services digital network 
(ISDN) connection. As shown, both calling party 101 and called party 106 
are connected to line adapters 502 and 504, respectively, to match the 
type of telephone equipment and subscriber loop characteristics to the 
standard Basic Rate Interface (BRI). The digital BRI signal contains two 
bearer channels plus one data channel (2B+D). The data channel (D) is 
typically used for signaling purposes. J. Bellamy, "Digital Telephony", 
Chapter 9.3 describes the BRI interface in greater detail and is herein 
incorporated by reference in its entirety. 
Generally, ISDN network interfaces 512 and 514 direct D channel signaling 
information to signaling network 132. The voice carrying B-channel, on the 
other hand, is routed through a circuit switched or channel switched 
digital network to reach the terminating party. By monitoring the D 
channel information, particularly from a called party, an ISDN network can 
receive, validate, and act upon requests for alternate billing in a manner 
similar to that outlined in FIG. 4. 
More generally, the implementation of alternate billing arrangements can be 
used in various environments that include switched connections established 
for standard voice communication, data communication, video conferencing, 
etc. These switched connections are available in various bandwidths 
including voice grade channels (DSO), T1 channels, STS-1 channels, etc. 
Recognition of alternate billing requests are implementation dependant and 
may include in-band or out-of-band signaling requests. 
While the invention has been particularly shown and described with 
reference to preferred embodiments thereof, it will be understood by those 
skilled in the relevant art that various changes in form and details may 
be made therein without departing from the spirit and scope of the 
invention.