BACKGROUND OF THE INVENTION Current call centers generally comprise some form of switching system (usually a private branch exchange or PBX), a server and a plurality of agent stations. The server is either a part of the switching system or a separate processor, such as a personal computer, with interface cards to support analog or digital connections to the switching system. In these systems, a call is received at the PBX and delivered to the server. The server screens the call and delivers the call to an appropriate idle agent position.

Current agent positions are tightly coupled to the switching system supporting them.

In many cases, there is a nailed up (permanent) connection between the switch and the agent station. In other call centers, a personal computer (desktop) application combined with some form of telephone (usually a headset) is connected to the switch system via digital lines.

All of these agent positions have a dedicated signaling channel to communicate with the server and the switch. When an agent position changes state (log on, log off, temporarily unavailable, etc.), the server must be notified so that it can route calls appropriately. Such notification requires the signaling link or channel between the agent position and the server so that the two can communicate. Most signaling channels are proprietary links requiring special equipment and software. Thus, any changes in functionality of the call center or agent positions requires changes in the switching system, server and/or the agent position. Further, adding new agent stations requires expensive, special purpose equipment.

SUMMARY OF THE INVENTION According to one aspect of this invention, any telephone that can generate dual tone multi-frequency (DTMF) signaling (also called touch-tone) may be used as an agent station.

In a call center that supports DTMF signaling from an agent station, a server is connected to

a switching system by a plurality of lines. The switching system includes a router, which, in response to a call to a predetermined telephone number, delivers the call to the server on a selected one of the plurality of lines and identifies the call as an agent position call. The server includes a DTMF detector that is connectable to the line to receive DTMF signaling from the agent position and a processor that is adapted to change the state of the agent position from its current state to a second state responsive to the DTMF signaling. Advantageously, the agent is presented with a menu of state selections depending on the agent's current state. In this manner, an agent can log on, log off and perform other tasks which in the past has required special signaling between the agent station and the switch.

According to another aspect of this invention, a call center is adapted to support at least one non-dedicated agent position, which operates in at least a current state and a second state. The call center includes a switching system connected to a server by a plurality of lines.

The switching system includes a router that is responsive to a predefined telephone number to deliver an incoming call to the server on one of the plurality of lines and to identify the call to the server as an agent position call. The server includes a DTMF detector connectable to the line to receive DTMF signaling from the agent position. The server further includes a processor connected to the DTMF detector that is adapted to change the state of the agent position from its current state to the second state responsive to agent position signaling detected at the DTMF receiver.

According to a further aspect of this invention, the server includes a voice prompt system that verbally prompts the agent position for DTMF signaling. According to another aspect of this invention, the server includes a plurality of ports connected to the plurality of lines, and a buss for connecting the plurality of ports to the DTMF detector and to the voice prompt. According to another aspect of this invention, the switching system is a private branch exchange.

According to yet another aspect ofthis invention, there are a plurality of non-dedicated agent positions wherein the server keeps track of the state of all agent positions in a database.

BRIEF DESCRIPTION OF THE DRAWINGS A more complete understanding of this invention may be obtained from a consideration of the following detailed description in conjunction with the drawings, in which:

Fig. 1 is a block diagram of a call center made according to an exemplary embodiment of this invention; Fig. 2 is a state diagram table illustrating changes of state performed in the server shown in Fig. 1; and Fig. 3 is a flow diagram illustrating the processing during a session with an agent position according to the exemplary embodiment of this invention.

DETAILED DESCRIPTION The vast majority of telephones in use today make use of dual-tone, multi-frequency (DTMF) technology to place calls and to perform other functions. The present invention makes use of the DTMF capability of such telephones to provide improved and expanded communication between a call center and a DTMF-capable telephone in the public telephone network.

Fig. 1 illustrates a block diagram of a call center, according to an exemplary embodiment of this invention, shown generally at 10. The call center 10 comprises a switching system illustrated here as a private branch exchange (PBX) 12 connected to a server 14 via a plurality of lines 16 and a control line 18. The PBX 12 is used here as an example. It should be recognized that any form of switching system would operate according to this invention depending on the desired size of the call center. The PBX 12 generally includes a controller 20 which controls call processing, as is known in the art. The PBX 12 also includes a router 22 which interconnects lines and/or trunks under control of the controller 20.

The server 14 is connected to the plurality of lines 16 at a plurality of ports 24. The ports 24 receive digital or analog signals from the PBX 12 and conventionally converts them into a form usable in the server 14. The ports 24 are connected to a buss 26 in this exemplary embodiment of this invention. The buss 26 provides a backbone interconnection for all of the components of the server 14. Of course, the buss 26 is merely illustrative and other configurations of the server 14 may be used.

The server 14 further includes a voice prompt unit 28. The voice prompt unit 28 stores and generates audible prompts requesting information from callers, and in this exemplary embodiment of this invention, prompts agent positions for signaling. A DTMF detector 30

listens on the buss 26 for DTMF signals arriving from the PBX 12 and translates the signals into digits. Such digits are reported to the processor 32 and used thereby to determine how the incoming call is to be handled. The processor 32 performs its task using programs and data stored in a memory 34 and an associated database 36. The processor 32 communicates with the controller 20 via a control line 18.

The call center 10 is connected to a public switch telephone network (PSTN) 50 via trunks and/or lines 52, as is known in the art. The PSTN 50 comprises a plurality of local switching systems, long distance systems, etc. For illustrative purposes, two agent positions 60 and 70 and a calling telephone 80 are shown, although quite obviously, many more are contemplated.

In normal operation, a caller at the calling telephone 80 dials a number (for example, an 800 number) to reach a call center. The call is routed through the PSTN 50 and the trunks 52 to the call center 10 at the PBX 12. The dialed telephone number is delivered along with the call. The controller 20, in response to the received telephone number, causes the router 22 to route the call over one of the lines 16. At the same time, the controller 20 informs the server 14 over the control line 18 of the incoming call and the specific line 16 that the call is on.

The server 14 receives the call at one of the ports 24 and causes the voice prompt 28 to present an audible menu to the caller. The DTMF detector 30 then monitors any signaling delivered from the calling telephone 80. When signaling is detected, digits corresponding to the signaling are delivered to the processor 32 which determines how to handle the call from records kept in the memory 34 and the database 36. Specifically, the processor 32 looks in the database 36 for an available agent position that can handle the specific type of call and notifies the PBX 12 of the destination agent position. The PBX 12 re-routes the call through the router 22, the trunks 52 and the PSTN 50 to one of the agent positions, for example, the agent position 60. The call is then completed.

The primary reason that an agent position is dedicated in the prior art is that control signaling requires special channels and equipment. Such control signals permit the agent to log in, log off, temporarily suspend operation ("not ready ") etc. Further, the agent may set up a special status for that particular position, i. e., handle only a prespecified type of call (such

as maintenance calls). In the non-dedicated call center architecture according to this invention, there is no special signaling connection between the agent positions 60 and 70 and to the PBX 12 or the server 14. In contrast, according to this invention, such communication signaling is provided using DTMF signaling.

In this exemplary embodiment, the agent position 70 is in an inactive state (it is not logged into the system) and thus does not receive calls. In order to log in, the agent at the agent position 70 dials a special telephone number which is routed through the PSTN 50 and the trunks 52 to the PBX 12. The controller 20 receives the dialed special telephone number (either through the trunk or a signaling network, not shown but well known in the art) and determines that this call is an agent position control call for the server 14 by the dialed special telephone number. The call is routed through the router 22 and one of the lines 16 to one of the ports 24. The controller 20 also notifies the processor 32 of the control nature of the call via the control line 18. The processor 32 then causes the voice prompt unit 28 to prompt the user to identify the agent station. Alternatively, an automatic number identification (ANI) may be delivered to the processor 32 so that the processor 32 can identify the calling agent station.

Once the identification of the agent station has been established, then the processor 32 determines what the state agent station 70 is currently in from the database record and prompts the agent station accordingly.

For example, now using Fig. 2 in conjunction with Fig. 1, if the agent station 70 is in an inactive state 200, the processor 32 causes the voice prompt unit 28 to prompt for signaling to change the state to the idle state 202 or the special state 204; in other words, the agent station 70 is ready to receive calls (the idle state 202) or ready to receive certain predefined types of calls (the special state 204). When the agent station 70 responds with DTMF signaling indicating the desired state, the processor 32 changes the agent station's record in the database 36 accordingly. The agent station 70 is then ready to receive calls according to the known art. The agent station 70 is changed from the idle state 202 to the busy state 206 by the processor 32 as calls are delivered and torn down between callers such as the caller 80 and the agent station 70. This change of state is not available to the agent station and is shown as a dotted line 208.

In another example, in response to a call to the special directory number from the agent position 70, the processor 32 checks the records in the database 36 for that agent position.

If the records for the agent station 70 indicate that it is in the idle state 202, the processor 32 may cause the voice prompt unit 28 to present a menu of current choices to move from the idle state 202. In the example of Fig. 2, the agent station 70 could select the inactive state 200, a special status 204, or a not ready status 210 (used when an agent is temporarily away from the agent position). Of course, these states are merely illustrative examples and many more states can be and are used in call centers than illustrated here.

Turning now to Fig. 3, a flow chart of operation according to an exemplary embodiment of this invention is shown. Processing starts in a box 300 where a call is received from the PBX 12 of a predefined agent position type (that is, the call was received at the special or predefined telephone number). Processing continues to a decision diamond 302 wherein a determination is made if the automatic number identification (ANI) of the agent position's telephone number has been received. There are some portions of the PSTN that do not deliver ANI. If the telephone number of the calling agent position is not received, processing proceeds to a box 304 where the agent station is prompted for its telephone number. Once that is received, processing moves to an action box 306 where the received telephone number is verified to be a valid agent position.

Processing continues to an action box 308 where a determination is made as to which state the agent station is in and proceeds to the action box 310 where a prompt is played which is appropriate to the specific state. For example, if the agent station 70 is in the inactive state 200, then the agent station 70 is prompted to whether it should be changed to the idle state 202 (ready to accept calls) or the special state 204 (ready to accept calls of specific calls types).

If the records for the agent station 70 indicates that it is in the idle state 202, then the agent station 70 is prompted, for example, for a change of state to the inactive state 200, the special state 204, or the not ready state 210. The agent at the agent station 70 enters a number at a dial tone multi-frequency (DTMF) keypad. The DTMF detector 30 receives the DTMF signaling and delivers the numeric equivalent to the processor 32. In a decision diamond 312, a determination is made whether a valid response was entered. If a valid response was not

entered, then processing proceeds back to the action box 310 where the user is again prompted.

If a valid response is received in the decision diamond 312, then processing proceeds to an action box 314 where the state of the agent station is changed according to the signaling entered. Processing proceeds to a decision diamond 316 where the agent station is prompted for further action. If, in the decision diamond 316, further action is requested, then processing loops back to the action box 310, where a prompt for the appropriate current state is played.

This prompt may not be the same as the one that is first played. If no further action is required in the decision diamond 316, then processing ends in a box 318.

It will therefore be apparent that the invention economically and simply provides a means of providing a call center supported by non-dedicated agent position through the unique use of the existing DTMF signaling capability of the vast majority of telephones in use today.

Consequently, the need for expensive, special signalling channels is avoided. By the same token, system functionality changes do not require switching system changes to thereby provide a very serviceable system. lt will further be appreciated that the invention may be added to existing call center equipment, with little additional hardware and software.

It is to be understood that the above-described embodiment is to illustrate the principles of this invention, and that those skilled in the art may devise many variations without departing from the scope of the invention. It is, therefore, intended that such variations be included within the scope of the appended claims.