Data/voice/fax compression multiplexer

• US 6,515,984 B1
• Filed: 11/13/2000
• Issued: 02/04/2003
• Est. Priority Date: 04/19/1994
• Status: Expired due to Fees

• Current Assignee: Multi-Tech Systems Incorporated
• Original Assignee: Multi-Tech Systems Incorporated
• Inventors: Arimilli, Harinarayana, Kanchan, Vasant Kumar, Thanawala, Ashish A.
• Primary Examiner(s): Vu, Huy D.
• Assistant Examiner(s): Nguyen, Steven
• Application Number:
  US09/711,754
• Time in Patent Office: 813 Days
• Field of Search: 370/352, 370/353, 370/354, 370/355, 370/356, 370/401, 379/93
• US Class Current: 370/352
• 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. Communication between the first site by voice or facsimile and the second site is transparent to the users. The multiplexer efficiently allocated the bandwidth of the composite link by detecting silence periods in the voice signals and suppressing the sending of the voice information to preserve bandwidth.

The transmission of facsimile information is performed by decoding the fax transmissions, sending only the facsimile image packets over the multiplexed composite link and reassembling, with carrier, the facsimile signals at the remote site for transmission over an analog telephone line to a remote facsimile machine.

Claims

1. A multiplexer, comprising:

a local area network (LAN) data interface means;

collection means for collecting LAN data from the LAN data interface means, and for producing therefrom collected LAN data packets;

a telephone interface means 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;

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

means for transmitting the data stream.

2. The multiplexer of claim 1, wherein the data stream includes a synchronous data stream.

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

4. The multiplexer of claim 3, wherein the data stream includes a synchronous data stream.

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

6. A method comprising:

receiving analog voice information signals;

digitizing the analog voice information signals to produce digital voice information;

compressing the digital voice information to produce compressed voice information packets;

collecting local area network (LAN) data and producing therefrom LAN data packets;

multiplexing the compressed voice information packets with the LAN data packets to produce a data stream; and

sending the data stream over a composite link.

7. The method of claim 6, wherein multiplexing the compressed voice information packets with the LAN data packets to produce a data stream includes multiplexing the compressed voice information packets with the LAN data packets to produce a synchronous data stream.

8. A multiplexed information network, comprising:

a first multiplexer having a first telephone line interface, a first local area network (LAN) data port, a first data processor connected for receiving LAN data from the first LAN data port and for placing the LAN data into LAN data packets each having separate headers, a first voice channel circuit means connected for receiving voice signals from the first telephone line interface and for digitizing and compressing the voice signals into compressed voice packets each having separate headers, the first data processor further operable for receiving the compressed voice packets from the voice channel circuit means and for multiplexing the LAN data packets and the compressed voice packets into a data stream, and the first data processor further connected to a first line interface for transmitting the data stream;

a second multiplexer having a second telephone line interface, a second LAN data port, a second data processor connected to a second line interface for receiving the data stream, the second data processor operable for demultiplexing the data stream to reproduce the LAN data packets and the compressed voice packets and for sending the compressed voice packets to a second voice channel circuit means, the second data processor further operable for removing the LAN data from the LAN data packets and for sending the LAN data to the second LAN data port, the second voice channel circuit means operable for decompressing and decoding the compressed voice packets to reproduce the voice signals and connected for sending the voice signals to the second telephone line interface; and

a composite link connected between the first line interface of the first multiplexer and the second line interface of the second multiplexer.

9. The network of claim 8, wherein the first telephone line interface of the first multiplexer is connected to a PBX and wherein the second telephone line interface of the second multiplexer is connected to a telephone.

10. The network of claim 8, wherein the first telephone line interface of the first multiplexer is connected to a PBX and wherein the second telephone line interface of the second multiplexer is connected to a PBX.

11. The network of claim 8, wherein the first telephone line interface of the first multiplexer is connected to a telephone and wherein the second telephone line interface of the second multiplexer is connected to a telephone.

12. The network of claim 8, wherein the composite link is an analog network link.

13. The network of claim 8, wherein the composite link is a digital network link.

14. The network of claim 8, wherein the composite link is an analog telephone line.

15. The network of claim 8, wherein the composite link is an analog leased line.

16. The network of claim 8, wherein the composite link is a public telephone line.

17. The network of claim 8, wherein the composite link is a private leased line.

18. The network of claim 8, wherein the composite link is a digital line.

19. The network of claim 8, wherein the first multiplexer comprises:

means for determining a link speed between the first multiplexer and the second multiplexer;

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

means for 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; and

means for 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.

20. A multiplexer, comprising:

a local area network (LAN) data interface;

collection means for collecting LAN data from the LAN data interface, and for producing therefrom collected LAN 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 LAN data packets for receiving the compressed digital voice data packets and for multiplexing the collected LAN data packets and the compressed digital voice data packets into a data stream, the multiplexer means including;

means for determining a link speed between the multiplexer and a second site;

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

means for 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; and

means for 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; and

means for transmitting the data stream.

21. The multiplexer of claim 20, wherein the data stream includes a synchronous data stream.

22. The multiplexer of claim 20, 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 LAN data packets, the compressed digital voice data packets and the facsimile data into a data stream.

23. The multiplexer of claim 22, wherein the data stream includes a synchronous data stream.

24. The multiplexer of claim 20, wherein the telephone interface further includes PBX interface means for connecting to a PBX for exchange of voice or facsimile signals.