Device and method for establishing a call connection

• US 6,426,942 B1
• Filed: 10/05/1998
• Issued: 07/30/2002
• Est. Priority Date: 10/17/1997
• Status: Expired due to Fees

• Current Assignee: Alcatel SA (Nokia Corporation)
• Original Assignee: Alcatel SA (Nokia Corporation)
• Inventors: Kopp, Dieter, Sienel, Jürgen
• Primary Examiner(s): Hsu, Alpus H.
• Assistant Examiner(s): Qureshi, Afsar M.
• Application Number:
  US09/166,611
• Time in Patent Office: 1,394 Days
• Field of Search: 370/229, 370/352, 370/353, 370/357, 370/360, 370/521, 370/235, 370/236, 370/354, 370/356, 704/500, 704/503, 375/240, 379/88.17, 379/93.01, 379/93.02, 379/93.05, 379/93.06, 379/93.09, 379/235, 379/236
• US Class Current: 370/235
• CPC Class Codes: H04M 7/0057 Services where the data services network provides a telephone service in addition or as an alternative, e.g. for backup purposes, to the telephone service provided by the telephone services network
• CPC Class Codes: H04M 7/006 Networks other than PSTN/ISDN providing telephone service, e.g. Voice over Internet Protocol (VoIP) , including next generation networks with a packet-switched transport layer H04L65/00 takes precedence; aspects not specific to the type of network H04M3/00; special services in those networks H04M3/42

Abstract

Call connections by way of the Internet (internet telephony) are less expensive than ones by way of an open telephone network. However, no fixed transmission rates are guaranteed in the Internet, which can lead to losses in the quality of transmitted speech signals. A device (V) for establishing a call connection between two subscriber terminals (T1, T2) has a first interface (IF1) to a packet-switched data network (INET) and means (IP, KOMP) for establishing connections by way of the packet-switched data network (INET) as well as a second interface (IF2) to a connection-oriented telecommunication network (PSTN), in which a transmission channel with a predetermined transmission band width can be furnished. By means of a monitoring device (MON), the device (V) determines a current data throughput in the data network (INET). A control device (SW) of the device (V) compares the current data throughput with a predetermined threshold value and controls the establishment of connections in such a way that the call connection is established by way of the data network (INET) when the data throughput lies above the threshold value and is established by way of the telecommunication network (PSTN) when the data throughput lies below the threshold value.

Claims

1. A device (V) for establishing a call connection between at least two subscriber terminals (T1, T2), which has a first interface (IF1) to a packet-switched data network (INET) and means (IP, KOMP) for establishing connections by way of the packet-switched data network (INET), characterized by means of

a second interface (IF2) to a connection-oriented telecommunication network (PSTN), in which a transmission channel with a set transmission band width can be furnished,

a monitoring device (MON) for determining a current data throughput in the data network (INET),

a control device (SW) for comparing the current data throughput with a set threshold value and for controlling the establishment of connections in such a way that the call connection is established by way of the data network (INET) when the data throughput lies above the threshold value and is established by way of the telecommunication network (PSTN) when the data throughput lies below the threshold value.

2. The device according to claim 1, in which the monitoring device (MON) repeatedly detects a current data throughput in the data network and the control device (SW) controls the establishment of connections during a call in such a way that an existing call connection established by way of the data network (INET) is re-established by way of the telecommunication network (PSTN) when the current data throughput lies below the threshold value.

3. The device according to claim 1, in which the monitoring device (MON) repeatedly detects a current data throughput in the data network (INET) and the control device (SW) controls the establishment of connections during a call in such a way that an existing call connection established by way of the telecommunication network (PSTN) is re-established by way of the data network (INET) when the current data throughput lies above the threshold value.

4. The device according to claim 2, in which the control device (SW) controls the establishment of connections in such a way that a new establishment of connection by way of the telecommunication network (PSTN) only occurs when the current data throughput falls below the threshold value by at least a predetermined difference value.

5. The device according to claim 3, in which the control device (SW) controls the establishment of connections in such a way that a new establishment of connection by way of the data network (INET) only occurs when the current data throughput exceeds the threshold value by at least a predetermined difference value.

6. The device according to claim 2, in which the current data throughput is integrated with a predetermined time constant before the comparison with the threshold value.

7. The device according to claim 1, in which the control device (SW) controls the establishment of connections using a criterion based on comparing the current data throughput with the set threshold value and also using at least one other criterion in such a way that a call connection is always established by way of the communication network (PSTN) when a predetermined condition is fulfilled with regard to the at least one other criterion.

8. A subscriber terminal (T1) in which two channels to a digital, connection-oriented communication network (PSTN) can be furnished in parallel, characterized in that it contains a device (V) for establishing a call connection between the subscriber terminal (T1) and another subscriber terminal (T2), the device (V) having a first interface (IF1) to a packet-switched data network (INET) and means (IP, KOMP) for establishing connections by way of the packet-switched data network (INET), the device (V) in turn characterized in that it includes:

a second interface (IF2) to a connection-oriented telecommunication network (PSTN), in which a transmission channel with a set transmission band width can be furnished,

a monitoring device (MON) for determining a current data throughput in the data network (INET),

a control device (SW) for comparing the current data throughput with a set threshold value and for controlling the establishment of connections in such a way that the call connection is established by way of the data network (INET) when the data throughput lies above the threshold value and is established by way of the telecommunication network (PSTN) when the data throughput lies below the threshold value,

wherein the first interface (IF1) and the second interface (IF2) are respectively connected to one of the two channels, and further wherein a connection to a provider of the packet-switched data network can be furnished by way of the channel connected to the first interface (IF1).

9. A telecommunications system (PABX1, PABX2) having a large number of connections for subscriber terminals (T1, T2), characterized in that it includes a subscriber terminal (T1) that in turn includes a device (V) for establishing a call connection between the subscriber terminal (T1) and another subscriber terminal (T2), the device (V) having a first interface (IF1) to a packet-switched data network (INET) and means (IP, KOMP) for establishing connections by way of the packet-switched data network (INET), the device (V) in turn characterized in that it includes:

a second interface (IF2) to a connection-oriented telecommunication network (PSTN), in which a transmission channel with a set transmission band width can be furnished,

a monitoring device (MON) for determining a current data throughput in the data network (INET),

a control device (SW) for comparing the current data throughput with a set threshold value and for controlling the establishment of connections in such a way that the call connection is established by way of the data network (INET) when the data throughput lies above the threshold value and is established by way of the telecommunication network (PSTN) when the data throughput lies below the threshold value,

wherein in providing at least one of the connections for the subscriber terminal (T1), the control device (V) couples either the first interface (IF1) or the second interface (IF2) to the subscriber terminal (T1).

10. A method for establishing a call connection from a calling subscriber terminal (T1), which is connected to a device (V) for establishing the call connection, to at least one called subscriber terminal (T2), with the following steps:

connection of the calling subscriber terminal (T1) with a packet-switched data network (INET) by way of a first interface (IF1) of the device (V),

connection of the calling subscriber terminal (T1) to a connection-oriented telecommunication network (PSTN), in which a transmission channel with a predetermined transmission band width can be furnished, by way of a second interface (IF2) of the device (V),

determination of a current data throughput in the packet-switched data network (INET),

comparison of the current data throughput with a predetermined threshold value, and

control of the establishment of connections in such a way that the call connection is established by way of the data network (INET) when the data throughput lies above the threshold value and is established by way of the communication-oriented telecommunication network (PSTN) when the data throughput lies below the threshold value.