Multiplex communications – Special services – Conferencing
Reexamination Certificate
1994-12-20
2002-05-28
Rao, Seema S. (Department: 2661)
Multiplex communications
Special services
Conferencing
C370S419000, C370S421000, C370S462000, C370S463000, C370S468000, C348S014090, C379S202010
Reexamination Certificate
active
06396816
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the field of digital communications. More particularly, the present invention relates to a digital communication system and method for efficiently transferring digital information between multiple terminals over a single channel communication link.
2. Background Art Related to the Invention
In anticipation of the increased need to transmit digital information rapidly across a substantial distance, the telephone industry has developed a digital communication link which enables a twisted pair of copper lines to transfer a substantial amount of digital information from one terminal to another with only minimal modification of prior installed telephone hardware. This digital communication link is referred to as an Integrated Services Digital Network (“ISDN”) which is well known in the art and defined by International Telegraph and Telephone Consultative Committee (“CCITT”). In recent years, the telephone industry has begun to utilize a sub-category of ISDN; namely, a Narrow-band Integrated Services Digital Network (“N-ISDN”) which partitions data into several channels. A further sub-category, well-known but still in development, is a Broad-band ISDN (“B-ISDN”) which partitions data into even more channels than N-ISDN.
Referring to
FIG. 1
, a conventional N-ISDN system
100
generally is configured with a terminal coupled at one end of a dedicated ISDN communication link and a remote terminal coupled to the other end of the ISDN communication link. A “terminal” represents either a device (e.g., a computer, facsimile machine, digital telephone, etc.) which produces at least one digital data stream at sixty-four (64) kilobits per second (“ISDN terminal”) or a “non-ISDN terminal” being any other device with a serial RS-232 port. As shown, a non-ISDN terminal
105
, more specifically its serial port
110
, is coupled to a terminal adapter
115
through a coaxial cable line
120
. The terminal adapter
115
enables older generation terminals to be compatible with ISDN protocols. It is contemplated that the terminal adapter
115
may be employed within the terminal
105
or externally as shown.
The terminal adapter
115
is coupled to an interface connector
125
through a bi-directional digital line
126
. The interface connector
125
is coupled between the bi-directional digital line
126
and a corresponding dedicated, pre-configured ISDN communication link
130
. If the ISDN communication link
130
is a N-ISDN communication link, the interface connector
125
is configured as a “basic rate interface” being well known in the art for supporting digital transmissions of up to 192 kilobits per second (“kb/s”) with framing bits. A typical embodiment of the basic rate interface provides two bi-directional, sixty-four (64) kb/s information channels and one bi-directional sixteen (16) kb/s control channel. In addition to these three channels, other supplemental channels may be available, for example, a twelve (12) kb/s channel for framing/timing and a four (4) kb/s channel for overhead to support network operations. It is further contemplated that the interface connector
125
may be configured as a “primary rate interface” if the ISDN communication link
130
is a B-ISDN communication link.
The ISDN communication link
130
is coupled to a second terminal adapter
135
remotely located from the terminal
105
. The second terminal adapter
135
also is coupled to a remote terminal
140
. As a result, the conventional N-ISDN system enables the terminal
105
to transmit information to and receive information from the remote terminal
140
. However, there are several disadvantages associated with this conventional ISDN system.
One disadvantage is that conventional ISDN systems do not efficiently utilize available bandwidth. For example, bit streams containing information crucial in maintaining acceptable communications between terminals are not given greater priority than other transmissions. Another example is that conventional ISDN systems utilize two fixed bandwidth channels to support digital transmissions. In the event that a specific terminal is not using a substantial portion of bandwidth provided in one or both of these channels, a likely situation since different amounts of bandwidth may be required for different compression needs, certain transmissions and/or operations may be delayed or precluded.
Yet another disadvantage is that multiple ISDN communication links and interface connectors are required to support multiple terminals. The additional costs associated with these connectors and ISDN communication links effect the general affordability of the conventional ISDN system.
Hence, it is desirable to provide a method and apparatus for supporting communications through a single connector over a single channel communication link (preferably an ISDN link) in order to reduce additional costs associated with multiple interface connectors. It is further desirable to configure the apparatus and method to efficiently allocate available bandwidth of the ISDN communication link to support real-time, interactive communications.
BRIEF SUMMARY OF THE INVENTION
A method and apparatus for providing digital information in a multiple interactive environment over a single communication link is described. Information, such as audio, control data and video, is generated by at least one terminal and is transmitted from the terminal to a resource allocation device. The resource allocation device (i) determines what portion of that information will be transmitted over the communication link, (ii) constructs information packets according to the allocated bandwidth and (iii) controls the multiplexing of the information packets.
REFERENCES:
patent: 4965798 (1990-10-01), Mostaja et al.
patent: 5132966 (1992-07-01), Hayano et al.
patent: 5231631 (1993-07-01), Buhrke et al.
patent: 5367517 (1994-11-01), Cidon et al.
patent: 5392223 (1995-02-01), Caci
Astle Brian
Pohlman William
Blakely , Sokoloff, Taylor & Zafman LLP
Intel Corporation
Rao Seema S.
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