Method for determining free agent communication terminal apparatus in communication networks with an automatic call distribution

The method relates to a group (G) of agent communication terminal apparatus (AKE) that are distributed over several communication systems (KS1, 2) of a communication network. If, given an incoming call (ar) in a communication system (KS1), no allocated agent communication terminal apparatus (AKE) is still free for the respective group (G), a resource request (ra) is transmitted to communication systems (KS2) to which agent communication terminal apparatus (AKE) of the same group (G) are connected. Using a response (aw), the addressed communication systems (KS2) indicate whether one of the agent communication terminal apparatus (AKE) is free or whether they are all occupied. After the signaling of a free agent communication terminal apparatus (AKE), the incoming call (ar) is switched to the respective communication system (KS2). With the method, the groups (G) of agent communication terminal apparatus (AKE) are distributed to several communication systems (KS1, 2), with efficient and uniform utilization thereof.

BACKGROUND OF THE INVENTION 
For a convenient distribution of incoming calls in communication systems of 
a communication network to predetermined groups of agent communication 
terminal apparatus, they are equipped with an automatic call distribution 
function. The automatic call distribution (also known as ACT among those 
skilled in the art) is essentially realized by a data processing 
installation connected to the respective communication systems, such as 
e.g. an ACD server. For the communication exchange between the 
communication system and the ACD server, an ACL (Applications Connectivity 
Link) interface is provided in both installations. As a transmission 
procedure, the MSV1 procedure or another transmission protocol can for 
example be used. A program structure is implemented in the communication 
system, by means of which structure both the switching-oriented events (in 
particular the incoming calls) are signaled to the ACD server through 
event messages, and also switching-oriented instructions transmitted by 
the ACD server via the ACL interface are brought to execution. In relation 
to an automatic call distribution, these are in particular the reswitching 
of incoming calls to agent communication terminal apparatus determined by 
the automatic call distribution. 
With an automatic call distribution, a group of agent communication 
terminal apparatus is allocated to one or more service numbers, e.g. 
several call accept positions are allocated to a call number of a company. 
A service number hereby represents a service communication connection 
(represents a line group with a call folder) to which the agent 
communication terminal apparatus that form the desired group are 
allocated. An incoming call, initialized by dialing a service number in an 
internal or external communication terminal apparatus, is switched through 
to the line group and is kept there in the call folder. At the same time, 
the arrival of a call for this service number is signaled to the ACD 
server through corresponding event messages. By means of the automatic 
call distribution implemented in the ACD server, a free agent 
communication terminal apparatus of the group is determined, and the 
incoming call is switched or, respectively, reswitched to the determined 
agent communication terminal apparatus. The reswitching is brought about 
by means of a switching-oriented instruction transmitted to the 
communication system by the ACD server. By means of the automatic call 
distribution, incoming calls can be held in a waiting queue, music or 
messages can be inserted during the hold time, and if all agent 
communication terminal apparatus are occupied, these calls can be 
forwarded to recording and answering equipment or can be rejected. 
In addition, in future communication networks with an automatic call 
distribution, the agent communication terminal apparatus of a group can be 
distributed over several communication systems, i.e. incoming calls of a 
group are to be switched to further communication systems in case of 
occupied agent communication terminal apparatus of a communication system. 
No method for realizing groups of agent communication terminal apparatus 
that overlap communication systems is currently known. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a communication network 
with automatic call distribution in which incoming calls can be switched 
to a free agent communication terminal apparatus of a group of agent 
communication terminal apparatus that are distributed over several 
communication systems. 
In general terms the present invention is a method for determining free 
agent communication terminal apparatus in communication networks with an 
automatic call distribution. Incoming calls addressed to a service number 
are respectively switched to a free agent communication terminal apparatus 
of a communication system, which is selected through the automatic call 
distribution from a group of agent communication terminal apparatus 
allocated to the service number. The agent communication terminal 
apparatus allocated to the group are distributed via several communication 
systems of the communication network. Given a call with a service number 
coming into a communication system, for which call there is no longer a 
free agent communication terminal apparatus in the allocated group of this 
communication system, resource requests are formed and are transmitted to 
those communication systems to which agent communication terminal 
apparatus of the respective group are distributed. In each communication 
system that receives a resource request the availability of an agent 
communication terminal apparatus allocated to the respective group is 
determined. A response is formed and is transmitted to the requesting 
communication system. A communication system with a free agent 
communication terminal apparatus of the respective group is identified in 
the requesting communication system from the transmitted response. The 
incoming call is further switched to the identified communication system 
by means of the automatic call distribution in the sense of a switching to 
the free agent communication terminal apparatus. 
An important aspect of the inventive method is that given an incoming call, 
with a service number, to a communication system in which all agent 
communication terminal apparatus of the allocated group are occupied, a 
resource request is formed in the communication system and is selectively 
transmitted to those communication systems to which agent communication 
terminal apparatus of the respective group are connected. The respective 
group in one of the further communication systems can also be a different 
group with a different service number; however, this different group is 
incorporated into the respective group as an "overflow group," whereby in 
case of occupied agent communication terminal apparatus in a communication 
system an incoming call is to be forwarded to the "overflow group" of the 
further communication system. In the addressed communication systems, the 
respective group is monitored for a free agent communication terminal 
apparatus. A response is subsequently formed and is transmitted to the 
requesting communication system, whereby the response indicates a free 
agent communication terminal apparatus, or else that no such apparatus is 
free. The requesting communication system evaluates the responses and 
switches the incoming call to a further communication system indicating a 
free agent communication terminal apparatus, in which system the incoming 
call is switched to the free agent communication terminal equipment. 
The resource request and the response are transmitted either via the 
communication network that connects the communication systems or via an 
additional local communication network. In case of a transmission via the 
communication network (KN), additional control routines for this exchange 
of information are required in the communication systems, which routines 
are an additional dynamic load on the communication systems. Since to a 
large extent local networks are installed at the operating companies (also 
private operating companies), the transmission of information can 
advantageously take place via these. Since in addition the data processing 
installations that realize the automatic call distribution, such as e.g. 
personal computers, are standardly connected to the communication systems, 
the connection to a local network can advantageously take place directly 
at the data processing installation, and the exchange of information via 
the local network can be controlled by this installation, by which means 
the additional controlling of the exchange of information can be omitted 
in the communication systems, resulting in a considerable relief of the 
burden on these systems. 
Advantageously, given availability of one of the agent communication 
terminal apparatus allocated to the respective group, the determined agent 
communication terminal apparatus is reserved. That is it is no longer 
switched for further incoming calls. According to a further development of 
the inventive method, given a reservation, after the determination of a 
communication system signaling a free agent terminal communication 
apparatus, a reservation release is formed by means of the automatic call 
distribution for those communication systems that likewise signal a free 
agent communication terminal apparatus of the respective group, and this 
release is transmitted to the respective communication systems, whereupon 
the reservation of the agent communication terminal apparatus is removed 
in these. By means of this reservation release, the reservation of a free 
agent communication terminal apparatus is removed again in the shortest 
time, and is again available for the reception of further incoming calls 
of the respective group. This represents a maximal exploitation of the 
resource "agent communication terminal apparatus," but an additional 
signaling is required for the transmission of the reservation release. 
Alternatively, i.e. without the reservation release, according to a further 
advantageous construction of the inventive method, the reservation of the 
agent communication terminal apparatus of the respective group is removed 
after a predetermined time interval in the communication systems that 
transmit a response to the requesting communication system, provided that 
no reservation release for the respective agent communication terminal 
apparatus is received there. The waiting for this time interval does not 
represent the most efficient use of the resource "agent communication 
terminal apparatus," but the respective communication system is 
dynamically relieved of stress by the omission of the signaling for the 
transmission of the reservation release. 
According to a further advantageous development of the inventive method, in 
the communication systems that receive a resource request, after a 
determination of several free agent communication terminal apparatus of a 
group, that free agent communication terminal apparatus is selected to 
which no incoming call has been switched during the largest time interval. 
In this way, the most equal utilization possible of the agent 
communication terminal apparatus within a communication system is 
achieved. 
According to a further construction of the inventive method, in the 
requesting communication system after the reception of several responses, 
respectively indicating a free agent communication terminal apparatus of 
the respective group, the free agent communication terminal apparatus is 
chosen associated with the response in which the indicated communication 
system is preferred according to a predetermined sequence, and/or in which 
no incoming call has been switched to the indicated free agent 
communication terminal apparatus for the longest time interval, and/or in 
which the most agent communication terminal apparatus (AKE) of a group are 
free in the indicated communication system, and/or in which the average 
non-occupied time interval of all the agent communication terminal 
apparatus configured in the respective group is the longest. The indicated 
criteria for the selection of a free agent communication terminal 
apparatus can be combined arbitrarily, i.e. can also be differently 
combined from service number to service number or, respectively, from 
group to group.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 shows a communication network KN, represented by two communication 
systems KS1, 2, given as examples. The two communication systems KS1, 2, 
both realized in the same way, are respectively equipped with the function 
"automatic call distribution," known to those skilled in the art as ACD. 
The components are explained on the basis of the first communication 
system KS1, but however are realized in the second and further (not shown) 
communication systems in the same way. The first communication system KS1 
is connected with an ACD server ACD-S that essentially realizes the 
automatic call distribution. The ACL interface ACL, which controls and 
monitors the communication exchange, is formed in the first communication 
system KS1 and in the ACD server ACD-S by a program structure ACL and by a 
physical connection (not shown), e.g. a V.24 interface. In addition, a 
program structure ACD that realizes the automatic call distribution is 
implemented in the ACD server ACD-S. In the first communication system 
KS1, the program structure ACL is embedded in an integrated operating and 
maintenance server ISp that administers and monitors the first 
communication system KS1. A control unit ST that controls the first 
communication system KS1 is connected with the operating and maintenance 
server ISp and with a switching unit KF. 
Alongside the switching-oriented program (not shown), the control unit ST 
contains an ACD control program structure DGV, in which the 
switching-oriented connection states of incoming calls ar are acquired and 
are inserted into switching-oriented event messages ei and are transmitted 
to the ACD program structure ACD via the ACL interface ACL for evaluation. 
Conversely, switching-oriented instructions amo, formed in the ACD program 
structure ACD and transmitted via the ACL interface ACL to the ACD control 
program structure DGV are executed, e.g. connection reswitchings. In the 
switching unit KF, a line group SA with a call folder AO is configured by 
means of corresponding operating and maintenance inputs, to which a 
predetermined group G of agent communication terminal apparatus AKE is 
allocated. As explained above, in the second communication system KS2 a 
line group SA with a call folder AO is likewise configured, to which is 
allocated a group G of agent communication terminal apparatus AKE. Both 
groups G belong to the same group G of agent communication terminal 
apparatus AKE, for example, agent communication terminal apparatus AKE are 
a single company. The group G of the second communication system KS2 can 
also represent a different group of agent communication terminal apparatus 
(AKE) with its own service number (not shown). However, this different 
group, including the different service number, is indicated in the first 
communication system KS as an "overflow group" in addition to the 
respective group G, and is thereby to be regarded as incorporated into the 
respective group G, i.e. finally represents a group G. This therefore 
means that for an incoming call ar with service number sr, the agent 
communication terminal apparatus AKE of the respective group G, together 
with those of the other group in the second communication system KS, 
represent a single group G. 
In the first communication system KS1, a line group SA, including a call 
folder AO, is connected to a service communication connection SKA, and 
connection lines VL are connected via further communication connections 
KA, whereby a portion of the connection lines VL is guided to the second 
communication system KS2 and a further portion of the connection lines VL 
is guided to the further communication systems (not shown) of the 
communication network KN. The communication network KN represents for 
example a private communication network, whereby the further portion of 
the connection line VL are guided to communication systems in the private 
or in the public communication network (e.g. the public telephone 
network). The calls ar, with the corresponding call number (i.e. service 
number) sr, coming in via the further portion of the connection lines VL, 
are forwarded to the line group SA. A call folder AO is allocated to the 
line group, by means of which folder, together with the ACD control 
program structure DGV, the incoming call ar is kept, and, including the 
service number sr, is signaled by means of a switching-oriented event 
message ei via the ACL interface ACL of the program structure ACD for the 
automatic call distribution. This determines a free agent communication 
terminal apparatus AKE according to predetermined criteria, and forms a 
switching-oriented instruction amo, which is transmitted to the ACD 
control program structure DGV via the ACL interface ACL, by means of which 
program structure the incoming call ar is reswitched to the free agent 
communication terminal apparatus AKE. 
For an information exchange, in particular for the transmission of an 
inventive resource request ar, a response aw and a reservation release 
rfi, the ACD servers ACD-S are connected to a local network LAN. The local 
network LAN is realized by a local area network for ACD servers ACD-S that 
are spatially nearby, and is realized by a wide area network for ACD 
servers ACD-S that are spatially further away. In principle, all types of 
networks are suitable, such as bus networks, ring and star networks. 
Preferably, local networks LAN are provided, which are already available 
at the operators of private or public communication networks. The 
transmission of the resource request ar, the response aw and the 
reservation release rfi ensues in a manner corresponding to the 
transmission method or, respectively, transmission protocol used in the 
respective local network LAN. 
If in the respective communication system KS a free agent communication 
terminal apparatus AKE can no longer be found for an incoming call, and if 
the group G is distributed over several (two, in the exemplary embodiment) 
communication systems KS1, 2, the inventive method is used. The individual 
steps of the method are shown in the self-explanatory flow chart in FIG. 
2. 
FIG. 3 shows the structure of a resource request ra, a reservation release 
rfi and a response aw, which all comprise a communication system 
information ks1, 2 that represents the origin and target communication 
system KS1, 2. Subsequently, a line information li, which represents the 
physical communication connection KA that transmits the call ar 
respectively coming in the first, i.e. originating, communication system 
KS1, is inserted into the resource request ar and the response aw. The 
resource request ra additionally comprises a service number sr(1) that 
represents the allocated group G of agent communication terminal apparatus 
AKE in the first, i.e. originating, communication system KS1, and a 
service number sr(2) that represents the allocated group G of agent 
communication terminal apparatus (AKE) in the second, i.e. target, 
communication system KS2. A group of agent communication terminal 
apparatus AKE is unambiguously defined by a service number sr and can be 
addressed through this number. As already explained, the service numbers 
sr(1), (2) belonging to the respective group G in the first and second 
communication system KS1, 2 may be the same, but may also be different. In 
addition, group names GN (indicated by the designation GN in FIG. 3) can 
be indicated. 
In addition, a call number rnr is indicated in the response aw, indicating 
the free agent communication terminal apparatus AKEY, or an identification 
information ki indicating that no agent communication terminal apparatus 
AKE is free. By means of the call number rnr indicating the free agent 
communication terminal apparatus AKEY, an incoming call ar reswitched to 
another communication system KS2 can be switched immediately to the free 
agent communication terminal apparatus AKEY. Optionally, the response aw 
contains a set information mi indicating the number of agent communication 
terminal apparatus AKE of the respective group G that are still free, a 
non-occupied time interval nbt of the indicated free agent communication 
terminal apparatus AKEY and/or a . . . ! the average non-occupied time 
interval dnbt of all agent communication terminals apparatus AKE 
configured in the respective group G. By means of the optional information 
mi, nbt, dnbt, an advantageous evaluation is possible, given several 
responses aw received in a requesting communication system KS1, 2, and a 
more uniform and more efficient utilization of the resources of the agent 
communication terminal apparatus AKE allocated to a group G is possible. 
If the set information mi is indicated with each response aw, the 
communication system KS1, 2 having the most agent communication terminal 
apparatus AKE still free can be selected. If the non-occupied time 
intervals nbt are inserted into the responses aw, the free agent 
communication terminal apparatus AKE to which no incoming call ar has been 
switched for the longest time interval can be selected in the requesting 
communication system KS1. 
The selection of an agent communication terminal apparatus AKE that is 
still free, given several free agent communication terminal apparatus AKE, 
can alternatively also be carried out in the addressed communication 
system KS2. The selection is made in particular with regard to the 
non-occupied or, respectively, occupied times, and the number of agent 
communication terminal apparatus still free in the respective 
communication system KS1, 2. 
The inventive method is also to be used for several groups of agent 
communication terminal apparatus AKE (not shown), whereby the 
communication systems are to be correspondingly constructed with regard to 
the service communication connections SKA, the line groups SA including 
the call folder AO, and the program structures DGV. 
The invention is not limited to the particular details of the method 
depicted and other modifications and applications are contemplated. 
Certain other changes may be made in the above described method without 
departing from the true spirit and scope of the invention herein involved. 
It is intended, therefore, that the subject matter in the above depiction 
shall be interpreted as illustrative and not in a limiting sense.