Multiplex communications – Communication techniques for information carried in plural... – Combining or distributing information via time channels
Reexamination Certificate
1998-11-10
2004-04-06
Pham, Chi (Department: 2663)
Multiplex communications
Communication techniques for information carried in plural...
Combining or distributing information via time channels
Reexamination Certificate
active
06717962
ABSTRACT:
TECHNICAL FIELD
The invention concerns a method for establishing a digital communication link, in particular a digital voice link, between at least two subscriber terminals. The invention further concerns a subscriber terminal and a switching center for establishing the digital communication link.
BACKGROUND OF THE INVENTION
For digital telephone links, according to the ISDN standard, communication links are configured between two subscriber terminals at a standard transmission rate of 64 kbit/s per B channel. This is described, for example, in the article “Digitales Vermittlungssystem EWSD” [EWSD digital switching system] by K. Langner (Telekom Unterrichtsblätter, Vol. 46, 2, 1993). An originating subscriber negotiates the call request via a control channel (D channel) with a switching center, which then sets up the communication link.
According to ITU-T Recommendation I.460 (Facsimile III.8-Rec. I.460, 1993), it is possible in ISDN to use other transmission rates lower than 64 kbit/s, for example 8, 16, or 32 kbit/s, and then to adapt them to the transmission rate of a B channel. There furthermore exists the possibility of multiplexing several data signals with a lower transmission rate into one 64 kbit/s B channel.
SUMMARY OF THE INVENTION
It is the object of the invention to provide a method with which it is possible, in a digital telecommunications network, to establish between at least two subscriber terminals a communication link which is better adapted to the transmission bandwidth used by one subscriber. Further objects of the invention are to provide a subscriber terminal and a switching center which are suitable for carrying out the method.
The object is achieved by a method for establishing a digital communication link between an originating subscriber terminal and at least one called subscriber terminal, having the steps of requesting from a switching center a link from the originating subscriber terminal to the called subscriber terminal; and establishing the link at a standard transmission rate, further having the steps of selecting a new, lower value for the transmission rate; agreeing upon the new, lower value with the switching center; and switching the transmission rate of the link over to the new, lower value.
The object is also achieved by a subscriber terminal for establishing a digital communication link to at least one called subscriber terminal, having the following devices: means for requesting from a switching center a provisional link to the called subscriber at a standard transmission rate; means for selecting a new, lower value for the transmission rate; and means for agreeing with the switching center upon the new, lower value.
The object is still further achieved by a switching center for establishing a digital communication link between at least two subscriber terminals, having the following devices: means for establishing, at a standard transmission rate, a provisional link to a called subscriber terminal requested by an originating subscriber terminal; means for agreeing with the originating subscriber terminal upon a new, lower value for the transmission rate; and means for switching the transmission rate of the provisional link over to the new, lower value.
One advantage of the invention is that the available transmission capacity of a telecommunications network can be used more effectively, and that only as much transmission capacity as is actually necessary needs to be made available for a communication link. A further advantage is that if a call metering system depends on the maximum payload that can be transmitted via the communication link that is established, there is a cost economy in terms of call charges for the subscriber.
REFERENCES:
patent: 4153916 (1979-05-01), Miwa et al.
patent: 4953180 (1990-08-01), Fieschi et al.
patent: 4965787 (1990-10-01), Almond et al.
patent: 5023869 (1991-06-01), Grover et al.
patent: 5327576 (1994-07-01), Uddenfeldt et al.
patent: 5491565 (1996-02-01), Naper
patent: 5644570 (1997-07-01), Skalsky
patent: 5857147 (1999-01-01), Gardner et al.
patent: 6044082 (2000-03-01), Nygård et al.
patent: 6118834 (2000-09-01), Rasanen
patent: 6130879 (2000-10-01), Liu
patent: 6144464 (2000-11-01), Rupp et al.
patent: 6278693 (2001-08-01), Aldred et al.
patent: 6366580 (2002-04-01), Bradley et al.
patent: 3721047 (1988-01-01), None
patent: 19618470 (1997-11-01), None
patent: 0651542 (1995-05-01), None
“Digitales Vermittlungssystem EWSD” by K. Langner (Telekom Unterrichtsblatter, vol. 46, 2, 1993) [EWSD digital switch system].
ITU-T Recommendation I.460 (Facsimile III.8—Rec. I.460, 1993, Recommendation from the Blue Book.
CCITT Recommendation I.464, Geneva 1991.
ITU-T Recommendation I.460 (Facsimile III.8—Rec I.460, 1993) Integrated Services Digital Network (ISDN).
CCITT Recommendation I.464 Integrated Services Digital Network (ISDN), Overall Network Aspects and Functions, ISDN User-Network Interfaces.
Patent Abstract of Japan, 081726878, date of publication Feb. 7, 1996.
Patent Abstract of Japan, 59-127456, Jul. 23, 1984.
Digitales Vermittlungssystem EWSD (EWSD digital switching system) by K. Langner (Telekom Unterrichtsblatter, vol. 46, 2, 1993).
Kopp Dieter
Sienel Jürgen
Alcatel
George Keith M.
Pham Chi
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