Multiplex communications – Special services
Reexamination Certificate
1998-05-13
2003-03-04
Chin, Wellington (Department: 2664)
Multiplex communications
Special services
C370S360000, C370S410000
Reexamination Certificate
active
06529483
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a communication system, method and processing means for switching calls via a transmission network provided between two local networks. The telephone call is initiated by a subscriber of a first local network (e.g. in Düsseldorf) and transferred from the first local network to a remote transmission network which then switches the call to a second local network (e.g. in Munich) which then transfers the call to the target subscriber. In contrast to the local network, which is in direct contact with the subscriber and provides a service (e.g. invoicing, maintenance etc.) for him, the remote transmission network merely has the passive task of rapid switching, usually without directly accessing the two subscribers of the local networks.
The invention particularly relates to the problem of how the remote transmission network can be brought out of this purely passive state and be directly connected to the subscriber, without relying on information from the local networks.
The invention was entailed by the following considerations. In the past, the local networks as well as the transmission network were strictly and centrally managed by the same system operator, e.g. by the German Post Office. This has drastically changed, however, over recent years as a result of opening up this market for private bidders. Now it is also possible for the individual networks to be operated by different private bidders. In particular, various remote transmission networks are available too. If a new supplier wishes to launch the new remote transmission network on the market, the principal problem is always of course to entice new customers and to get them to use the new network based on attractive offers. Although this does in principle apply to the local network operators as well, such operators are able to contact new customers or subscribers directly in order to provide them with a service.
New suppliers of remote transmission networks are, however, faced with the problem of being dependent on information from the local network operators because they do not have any direct access to the subscribers. As shall be explained below, every call transferred from the local network does in fact receive an identification (a transmission network selection parameter) that the specific remote transmission network is supposed to be selected, but at the time of call initiation, the remote transmission network operator does not know which type of subscriber is calling, i.e. whether the subscriber himself or the local network has selected the specific remote transmission network.
THE INVENTION'S TECHNICAL BACKGROUND
The problems as to why the remote transmission network currently does not exhibit any access, particularly on-line access, to the local network subscribers will be described below with reference to the prior-art communication system shown in FIG.
11
.
FIG. 11
shows a first local network LN
1
(e.g. Deutsche Telekom), a second local network LN
2
(e.g. likewise Deutsche Telekom) and two remote transmission networks FN
1
, FN
2
for selecting the subscriber or the local network.
FIG. 11
shows the case in which the call is executed from subscriber A to subscriber B via the remote transmission network FN
1
, while a call by subscriber B to subscriber A is performed via the other remote transmission network FN
2
. The individual exchanges EX (e.g. just one EX is depicted in each network, although several EX may of course be provided) switch the individual calls within the networks, with standard signaling being performed between the networks using standard protocols (e.g. ETSI ISUP Version 2 (ISDN User Part) for the SIGNALLING SYSTEM No. 7, described in ITU-T Recommendation Q.763). In the communication system in
FIG. 11
, there are in principle two possible ways of selecting one of the remote transmission networks FN
1
, FN
2
, viz. “by contractual preselection” and “by subscriber selection”.
Transmission Network Selection by Contractual Preselection
As shown by the hatched line between A⇄FN
1
, subscriber A has made direct contact with the remote transmission network
1
and concluded an exclusive contract with this transmission network. Subscriber A or the remote transmission network
1
notifies this to the operator of local network LN
1
so that all the calls initiated by subscriber A are directed via FN
1
. If subscriber A dials the desired national telephone number NDC of target subscriber B, the local network then looks up in a local memory
1
-
1
whether a specific preselection for the remote transmission network was made on behalf of subscriber A. In this instance, memory
1
-
1
indicates that FN
1
is to be used. The local network together with a call set-up parameter block NDC, CSP
1
, CLI transfers the call set-up request to the remote transmission network
1
. In other words, the local network adds a prefix CSP
1
to the national telephone number NDC, whereby CSP
1
is the transmission network selection parameter envisaged for FN
1
. A call line identification parameter CLI identifying the subscriber station or subscriber from whom the call set-up request originates is also transferred by the local network. Since the remote transmission network FN
1
already contains information on subscriber A in an intelligent device IN for concluded contracts, it can identify subscriber A when a so-called black-and-white checking test is performed using a corresponding REG content. If a match exists, the remote transmission network FN
1
is able to transmit the bill for the exchange directly to the subscriber.
Transmission Network Selection by Subscriber Selection
In contrast thereto, subscriber B deliberately chooses the remote transmission network FN
2
during call initiation, whereas he has not previously concluded any contract with this network. Subscriber B himself inputs a preselection by means of the transmission network selection parameter CSP
2
together with the national telephone number NDC so that the local network LN
2
knows that the call from subscriber B has to be directed after FN
2
. Like the FN
1
network, the remote transmission network FN
2
also receives in this instance a call set-up parameter block consisting of NDS, CSP
2
, CLI. The remote transmission network FN
2
does not, however, find any kind of entry whatsoever in its intelligent device IN, because a contract with subscriber B does not yet exist. In this case, FN
2
has to transfer the bills for settlement of accounts to the local network LN
2
and does not have any direct access to subscriber B whatsoever. In other words, in instances where the standard transmission network selection parameter CSP is overwritten by a parameter CSP
2
set by the subscriber, the operator of the local network LN
2
and the operator of the remote transmission network FN
2
have to have reached contractual agreements.
This approach is not especially advantageous because a new operator of a new remote transmission network therefore always relies on cooperation with the local network operator. The only option available to the remote transmission network operator is simply not to permit the call, which is in turn far from beneficial since the remote network operator is after all dependent on customers. The only active intervention is therefore restricted to the black-and-white checking test shown in FIG.
12
.
Black-and-white Checking Test
In step S
1
, the remote transmission network FN
1
, FN
2
reads the call line identification parameter CLI and decides in step S
2
whether a test is to be performed using a black list or a white list. The black list contains entries about subscribers on whose behalf a contract has been concluded, whereas the black list contains entries for subscribers who have not concluded a contract. The left and right branches in
FIG. 12
are therefore analog.
If a corresponding entry indicating that a contract has been reached with a subscriber is found in step S
3
or S
4
, the call can be switched and processed (steps S
5
, S
6
). If no corresponding entry is
Chin Wellington
Telefonaktiebolaget LM Ericsson (publ)
Tran Maikhanh
LandOfFree
Communication system, method and processing means for... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Communication system, method and processing means for..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Communication system, method and processing means for... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3006687