Data/voice/fax compression multiplexer

• US 5,682,386 A
• Filed: 04/19/1994
• Issued: 10/28/1997
• Est. Priority Date: 04/19/1994
• Status: Expired due to Term

• Current Assignee: Multi-Tech Systems Incorporated
• Original Assignee: Multi-Tech Systems Incorporated
• Inventors: Arimilli, Harinarayana, Kanchan, Vasant Kumar, Thanawala, Ashish A.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): Nguyen, Chau T.
• Application Number:
  US08/229,958
• Time in Patent Office: 1,288 Days
• Field of Search: 370/79-81, 370/109, 370/110.1, 370/112, 370/118, 370/111, 370/85.6, 370/94.2, 370/60, 370/94.1, 370/85.7, 370/276, 370/472, 370/465, 370/473, 370/468, 370/470 , 370/471, 370/477, 370/522, 370/535, 370/536, 370/537, 379/93, 379/96, 379/53, 379/54, 379/100, 379/104, 375/245, 395/2.3, 395/2.32
• US Class Current: 370/468
• CPC Class Codes: H04J 3/1688 the demands of the users being taken into account after redundancy removal, e.g. by predictive coding, by variable sampling reducing bandwidth of signals in general H04B1/66; in PCM-systems H04B14/046; removal of redundancy in telegraph communication H03M7/30
• CPC Class Codes: H04J 3/247 ATM or packet multiplexing
• CPC Class Codes: H04L 2012/6427 Subscriber Access Module; Concentrator; Group equipment
• CPC Class Codes: H04L 2012/6459 Multiplexing, e.g. TDMA, CDMA
• CPC Class Codes: H04L 2012/6462 Movable boundaries in packets or frames
• CPC Class Codes: H04L 2012/6464 Priority
• CPC Class Codes: H04L 2012/6486 Signalling Protocols
• CPC Class Codes: H04L 2012/6494 Silence suppression
• CPC Class Codes: H04L 65/765 intermediate
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04M 1/253 Telephone sets using digital voice transmission
• CPC Class Codes: H04M 11/064 Data transmission during pauses in telephone conversation
• CPC Class Codes: H04N 1/00281 with a telecommunication apparatus, e.g. a switched network of teleprinters for the distribution of text-based information, a selective call terminal details of transmission H04N1/00095; establishing a communication with one of a facsimile machine or another apparatus sharing a single line H04N1/32704; interfacing cordless telephone terminals with an accessory to increase the functionality of user interface H04M1/72409
• CPC Class Codes: H04N 1/00302 with a telephonic apparatus, e.g. telephone answering machine or videotex terminal H04N1/00307 takes precedence; telephonic communication H04M
• CPC Class Codes: H04N 1/00312 with a digital transmission apparatus, e.g. a switched network of teleprinters for the distribution of text-based information, SMS or ISDN device transmitting or receiving via a computer, e.g. using e-mail, a computer network or the internet H04N1/00214; transmission of digital information H04L

Abstract

A data multiplexing network is described which multiplexes a plurality of asynchronous data channels with an asynchronous data stream representing compressed voice signals and/or facsimile signals onto a single synchronous data packet stream. The single synchronous data packet stream is then transmitted by a high speed statistical multiplexer over a composite link to a second site using a modified high-level synchronous data link control protocol with an overlay of a priority statistical multiplexing algorithm. The asynchronous data channels and the compressed voice channel and/or facsimile signals are demultiplexed and reconstructed for sending to other asynchronous computer terminals and to a standard telephone or facsimile analog port at the second site, respectively. PBX trunk interfaces are also provided to allow PBX'"'"'s to share the composite link between sites.

Claims

1. A data multiplexer, comprising:

a plurality of asynchronous data interfaces;

collection means for collecting the asynchronous data from the plurality of asynchronous data interfaces, and for producing therefrom collected asynchronous data packets each having a header;

a telephone interface for receiving voice band signals;

conversion means for converting the voice band signals into digital samples;

compression means for compressing and encoding the digital samples and for producing therefrom compressed digital voice data;

means for placing the compressed digital voice data into compressed digital voice data packets each having headers;

multiplexer means connected for receiving the collected asynchronous data packets, for receiving the compressed digital voice data packets and for multiplexing the collected asynchronous data packets and the compressed digital voice data packets into a synchronous data stream; and

means for transmitting the synchronous data stream.

2. The data multiplexer of claim 1 wherein the telephone interface is further operable for receiving facsimile data and the multiplexer means is further operable for receiving the facsimile data and for multiplexing the collected asynchronous data packets, the compressed digital voice data packets and the facsimile data into a synchronous data stream.

3. The data multiplexer of claim 1 wherein the telephone interface further includes PBX interface means for connecting to a PBX for exchange of voice or facsimile signals.

4. A method of performing priority statistical multiplexing, comprising the steps of:

determining the link speed between two sites;

selecting a time interval for sending high priority data packets each having a header;

dynamically assigning a packet size for a low priority data packet having a header with the packet size for the low priority data packet limited in length based upon the link speed and the time interval;

sending as many low priority data packets as will fit between the sending of high priority data packets within the time interval for sending high priority packets.

5. A method of sending voice data and asynchronous data over the same composite link having a link speed, comprising the steps of:

receiving analog voice signals;

digitizing the analog voice signals to produce digital voice data;

compressing the digital voice data to produce compressed voice data packets having headers;

selecting a time interval for sending compressed voice data packets;

collecting asynchronous data and producing therefrom asynchronous data packets having headers by dynamically assigning the asynchronous data packet size limited in length based upon the link speed and the time interval;

multiplexing the compressed voice data packets with the asynchronous data packets to produce a synchronous data stream; and

sending the synchronous data stream over a composite link.