Can conference calls be traced

 Can others see my number in a conference call?

When you join a conference call via phone (PSTN, not internet/VoIP), we now hide the last three digits of your phone number, as displayed on the Participants list. The meeting owner sees each participant's original number, but everyone else sees asterisks in place of the last three digits.

Conference call participation tracking

Abstract

A method and apparatus for tracking participation in a conference call is disclosed. A conference tracker at a first location transmits a status signal to another conference tracker at a second location. The conference tracker at the second location receives the status signal and recognizes it as representative of an attribute of one or more of the parties at the first location. The attribute represented may be the identity of the first location, thereby informing the conference tracker at the second location that the first location remains connected to the conference call. In this manner, the conference tracker may inform a party of the number of connected locations or that a particular location has disconnected. The attribute represented may be the identity of the first location when a party at that location is speaking. In this manner, the conference tracker at the second location may thereby inform a listening party of the location of the speaking party. The attribute represented may be the identity of the speaking party, thereby enabling the conference tracker at the second location to determine which party is speaking. Status signals transmitted by each conference tracker may comprise audio pulses of unique frequencies, thereby enabling each conference tracker to determine the origin of each status signal. Consecutive pulses may be used to identify a particular status (e.g., connected or speaking).

Description

This application is a continuation of application Ser. No. 08/066,456, filed on May 24, 1993, now abandoned.

FIELD OF THE INVENTION

The present invention relates generally to the field of telephone communication and more specifically to telephone conference calling.

BACKGROUND OF THE INVENTION

Telephone conference calls allow multiple parties to participate in a single conversation. Conference calls couple a plurality of locations (usually more than two) with use of a communication channel. At each location, there may be one or more parties (participating persons) to the conversation. Each location may include, for example, a conventional telephone set used by a single party, or a conventional speakerphone used by one or more parties. The communication channel supporting a conference call typically comprises a conventional switched telephone network. Should the communication channel include a wireless (e.g., cellular) communication link, one or more of the participating "locations" may comprise a mobile cellular phone or speakerphone.

Although a widely used tool in business and industry, telephone conference calls suffer from certain problems which impact on their effectiveness as a substitute for other methods of communication, such as a face-to-face meeting. For example, during a typical conference call, a party cannot be sure who else is on the line (Le., connected) at any given time. Moreover, unless a listener is familiar with the voice of each participant in the call, it may be unclear which party is speaking at any given time. Questions such as "John, are you still on the line?" or "Who just said that?" need to be asked frequently. Such difficulties can cause the conversation to become less productive and often uncomfortable or even embarrassing.

SUMMARY OF THE INVENTION

The present invention provides a technique for tracking the participation of parties in a conference call. A participating (first)location transmits a tracking signal to another participating (second)location. The second location receives the tracking signal and recognizes it as representative of an attribute of one or more of the parties at the first (transmitting) location. Such attributes may include, for example, the location of a party, the location of a party presently speaking, and the identity of a speaking party.

Illustratively, tracking signals are transmitted and received at each location by a conference call tracking device. Such a device is preferably interposed between a telephone deskset and handset, connected to each by standard 4-wire telephone cords.

According to a first illustrative embodiment of the present invention, the party attribute recognized by a tracking device at the second location is an identity of the (first) location of a party to the conference call. In this manner, parties at the second location may be made aware that the first location remains connected to the conference call. Moreover, the tracking device at the second location may monitor this tracking signal. If the signal has not been received for a predetermined amount of time, the tracking device at the second location may inform a party that the first location and hence the parties there are no longer participating in the call. In addition, a party at the second location may be informed of the number of locations which remain connected to the conference call at a given time.

According to a second illustrative embodiment, the attribute recognized by a tracking device at a second location is an identity of the first location when one of the parties at the first location is presently speaking. In this manner, parties at the second location may be made aware that the presently speaking party is located at the first location. Where there are more than two locations connected to the conference call, the listening party may thereby be apprised of the location of the speaking party.

According to a third illustrative embodiment, the attribute recognized by a tracking device at the second location is an identity of the speaking party at the first location. In this manner, parties at the second location may be made aware of the identity of the speaking party. Where there are more than two parties to the conference call, the listening party may thereby determine which party is speaking.

In any of the illustrative embodiments of the present invention, the tracking signals may comprise one or more audio pulses of a predetermined frequency within the frequency band of the channel supporting the conference call. These pulses are combined with speech signals by a tracking device and transmitted across the communication channel. The predetermined frequency of the audio pulses may then be filtered out by a receiving tracking device such that a listening party hears only speech and not the audio pulses.

Alternatively, the embodiments may divide the channel bandwidth into subbands. Tracking signals from a given location which comprise one or more audio pulses of a predetermined frequency may be transmitted within one of these subbands. Such subbands may be filtered out by a receiving tracking device such that a listening party hears only speech. This division of channel bandwidth into subbands may be performed dynamically based on the number of locations participating in the conference call. In this manner, the portion of the frequency band which is not filtered out is advantageously maximized for a given number of participating locations, thereby improving the audio quality of the resultant speech signal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the addition of a conference call tracking device to a conventional telephone set in accordance with one embodiment of the present invention.

FIG. 2 illustrates a block diagram of the conference call tracking device of FIG. 1.

FIG. 3 is a flow diagram illustrating the initialization of conference call tracking in accordance with an embodiment of the present invention.

FIG. 4 is a flow diagram illustrating the transmission of status signals from a participating location in accordance with an embodiment of the present invention.

FIG. 5 is a flow diagram illustrating a method of recognizing status signals at a participating location in accordance with an embodiment of the present invention.

FIG. 6 presents an allocation of the frequency spectrum according to one embodiment of the present invention.

DETAILED DESCRIPTION

For clarity of explanation, the illustrative embodiment of the present invention is presented as comprising individual functional blocks (including functional blocks labeled as "processors"). The functions these blocks perform may be provided through the use of either shared or dedicated hardware, including, but not limited to, hardware capable of executing software. (Use of the term "processor" should not be construed to refer exclusively to hardware capable of executing software.)

Illustrative embodiments may comprise digital signal processor (DSP) hardware, such as the AT&T DSP16 or DSP32C, read-only memory (ROM) for storing software performing the operations discussed below, and random access memory (RAM) for storing DSP results. Very large scale integration (VLSI) hardware embodiments, as well as custom VLSI circuitry in combination with a general purpose DSP circuit, may also be provided.

FIG. 1 illustrates a conventional telephone set with the addition of a conference call tracking device ("conference tracker") in accordance with an embodiment of the present invention. Conference tracker 28 is connected in-line on the "4-wire" side of a conventional telephone set, namely, between deskset 30 and handset 32. Alternatively, conference tracker 28 may be built into the telephone set as an adjunct component, also connected in-line on the 4-wire side of the instrument. Each party in a conference call may advantageously have conference tracker 28 included in either manner. Further alternate embodiments may comprise conference trackers which are connected on the 2-wire side of the instrument. Each conference tracker included in a conference call tracks the participation of parties at other locations. Moreover, conference tracker 28 enables conference trackers at other locations to track the participation of parties at the location of conference tracker 28.

FIG. 2 presents a block diagram of the illustrative conference tracker 28 of FIG. 1. Conference tracker 28 comprises digital signal processor (DSP) 12, codec 18, codec 20, read-only-memory (ROM) 14, random access memory (RAM) 16, control interface 22, display 24 and optional speakerphone 26. DSP 12 controls the operation of the device. Signals which pass between deskset 30 and handset 32 pass through and are monitored by DSP 12. DSP 12 may be implemented with a conventional digital signal processor such as the aforementioned AT&T DSP16.

Codec 18 converts analog signals from the deskset to digital format, and converts digital signals from DSP 12 to analog format. Similarly, codec 20 converts signals from the handset from analog to digital format and converts signals which are sent to the handset from digital to analog format. In this manner, all processing performed by DSP 12 is advantageously performed on digital signals. Codecs 18 and 20 may be implemented with conventional analog-to-digital and digital-to-analog converters.

ROM 14 stores program code to control the operation of DSP 12. In particular, the procedures illustrated in FIGS. 3-5 may be implemented in software and stored in ROM 14. ROM 14 may also store selected fixed data.

RAM 16 stores data which is used to recognize and identify status signals transmitted by conference trackers at other locations. In particular, the number of other locations currently connected to the conference call along with a representation of the (unique) status signal sent by each of the trackers at other locations is stored in RAM 16. In addition, RAM 16 may store identification data, by which each location or party to the conference call may be identified to parties at the location of the given conference tracker 28. This identification data may be stored in RAM 16 as text, representing, for example, the name of the given party or location.

Control interface 22 enables parties at the location of the given conference tracker 28 to control the operation of the tracking device. Control interface 22 may, for example, comprise conventional buttons which activate specific functions when pressed. Display 24 provides for the display of information to parties at the given location of conference tracker 28. Display 24 may be implemented with a conventional alphanumeric display, such as an LCD (liquid-crystal display).

Optional speakerphone 26 may be provided to enable the use of conference tracker 28 by multiple parties at the same location. Since it is preferred that conference tracker 28 be interposed on the 4-wire side of the telephone set, conventional speakerphone capability built into deskset 30 may be inadequate unless conference tracker 28 is also built into deskset 30. Therefore, it is advantageous to provide speakerphone 26 as an optional feature built into conference tracker 28. Speakerphone 26 comprises a microphone and a speaker, and may be implemented with conventional components.

According to one embodiment, conference tracker 28 transmits a "unique" identifying signal (referred to as a status signal) at regular intervals (referred to as cycles). A status signal from conference tracker 28 comprises, for example, one or more audio pulses of a frequency which is distinct from that frequency employed by any of the other conference trackers used in a conference call. In addition to transmitting such pulses, conference tracker 28 monitors the line to detect and recognize the unique status signals transmitted by the other conference trackers connected to the conference call. In so doing, conference tracker 28 may be continuously apprised of the status of the conference call on an individual location by location basis (e.g., which locations remain connected on the call).

Conference tracker 28 may use modified versions of the status signal to transmit information in addition to an indication that a location remains connected to the conference call. For example, according to one embodiment, two consecutive audio pulses of the conference tracker's assigned (unique) frequency may be transmitted when a party at the location of the transmitting conference tracker is speaking. When no party at that location is speaking, only one such pulse is transmitted by the tracker. In this manner, the other ("listening") conference trackers may be continuously apprised not only of which locations remain connected, but also of the location of a speaking party.

In accordance with another embodiment, a different version of the status signal may be transmitted depending on which particular party is speaking at a location having multiple parties. For example, each party at the location may be assigned a different number of pulses (greater than one) of the location's (conference tracker's) assigned audio frequency. Thus, a listening conference tracker may be able to identify for parties at its location not only the location of the speaking party ("speaking location"), but also the particular party who is speaking at that location.

FIGS. 3-5 present flow diagrams of procedures performed by an illustrative embodiment of the present invention. These procedures may be implemented in software. This software may be stored in ROM 14 and executed by DSP 12. The software implementing these procedures are advantageously executed as concurrent processes, i.e., executed simultaneously. If DSP 12 is not provided with a conventional multi-tasking or time-shared operating system environment, a simple conventional executive control program may be included. For example, such an executive control program might call each of the three processes in turn as a subroutine. Upon each such subroutine call, the main loop of the called subroutine is executed once, after which the subroutine returns control to the executive program.

FIG. 3 is a flow diagram illustrating the initialization of conference call tracking. At the inception of a conference call, a party at each location in turn presses an "initialize" button on control interface 22 of conference tracker 28. This activity may be instigated, for example, by a "roll call" initiated by a conference call chairperson. In particular, a chairperson might press the initialize button on his or her conference tracker and then provide the appropriate identity data as described in the discussion of step 38 below. Conference trackers at each other location may be similarly initialized in turn, in response to direction of the chairperson. While use of a chairperson can facilitate the initialization process, no chairperson is required according to the invention.

Specifically, the procedure of FIG. 3 recognizes that the initialization sequence for a given location is to be performed in decision step 34. Steps 36, 38, 40, 42, 44 and 45 are thereby performed. Since the status signal transmitted by conference trackers at each location is unique, step 36 determines which frequencies have already been assigned to trackers at other locations, and selects an available (unassigned) frequency for the conference tracker being initialized. The status signal for the initialized conference tracker will comprise one or more audio pulses of the frequency so determined.

Step 38 accepts data input from one or more parties at the given location. In one embodiment, this data will identify the location by a familiar name, such as the name of the organization or of the party (or one of the parties) at that location. In an alternative embodiment, each of a plurality of parties at the given location may input individual identity information (e.g., their names) so that individual speakers may be subsequently identified by other conference trackers. In this case, each party's identity information is input in turn, and each is associated with an "index" which may be subsequently used to distinguish the distinct parties at the given location.

The input accepted by step 38 may be provided by key entry. For example, the touch-tone keys on the deskset may be used to spell a name. These signals can then be subsequently converted to text, by, for example, conventional dual-tone multi-frequency (DTMF) recognition techniques. Alternatively, this data may be provided by speech input. A party may speak his or her name or the name of the organization into handset 32 (or speakerphone 26). This audio signal may be subsequently converted into a digitally encoded representation for convenient storage. Moreover, one of these two approaches to the input of identity information may be used and followed by a conversion to the other format internal to conference tracker 28. In other words, the information may be input as speech and then converted to text by the application of conventional speech recognition techniques. Alternatively, the information may be input as text (e.g., by key input) and then converted to an audio speech signal by the application of conventional speech synthesis techniques. In any case, the data obtained by step 38 may be stored in RAM 16 for subsequent transmission to other conference trackers participating in the conference call.

Step 40 begins the process of informing the other participating conference trackers about the given initialized conference tracker 28. In particular, step 40 transmits a predetermined "identify" signal (e.g., a pulse of a predetermined frequency distinct from the frequencies which are assigned to the tracking devices for their individual status signals) to inform the other conference trackers that identification data is forthcoming. Step 42 then transmits an audio pulse of the frequency which the given conference tracker 28 has assigned to itself at step 36, and step 44 transmits the identity information input at step 38. Where individual identity information is provided for each of a plurality of parties, step 44 may transmit data identifying each party individually. In this case, each party would be advantageously associated with a corresponding index. This index may be used, for example, to determine the number of consecutive status signal pulses which will be transmitted to represent that specific party when speaking