Dual port interface for a computer-based multifunction personal communication system

• US 5,619,508 A
• Filed: 03/23/1995
• Issued: 04/08/1997
• Est. Priority Date: 01/08/1993
• Status: Expired due to Term

• Current Assignee: Multi-Tech Systems Incorporated
• Original Assignee: Multi-Tech Systems Incorporated
• Inventors: Davis, Jeffrey P., Sharma, Raghu
• Primary Examiner(s): Chin, Wellington
• Application Number:
  US08/409,017
• Time in Patent Office: 747 Days
• Field of Search: 370/81, 370/80, 370/110.1, 370/76, 370/79, 379/101, 379/109, 379/108, 379/93, 379/96
• US Class Current: 370/495
• CPC Class Codes: G10L 19/04 using predictive techniques
• CPC Class Codes: H04L 12/6418 Hybrid transport
• CPC Class Codes: H04L 2012/6424 Access arrangements
• 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 2012/6475 N-ISDN, Public Switched Telephone Network [PSTN]
• CPC Class Codes: H04L 2012/6481 Speech, voice
• CPC Class Codes: H04L 2012/6491 Echo cancellation
• CPC Class Codes: H04L 2012/6494 Silence suppression
• CPC Class Codes: H04L 27/3416 in which the information is carried by both the individual signal points and the subset to which the individual points belong, e.g. using coset coding, lattice coding, or related schemes
• CPC Class Codes: H04L 65/1069 Session establishment or de-establishment
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/70 Media network packetisation
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04M 1/247 Telephone sets including user guidance or feature selection means facilitating their use user interfaces specially adapted for cordless or mobile telephones H04M1/724
• CPC Class Codes: H04M 1/2473 Telephone terminals interfacing a personal computer, e.g. using an API (Application Programming Interface) details of API H04M7/0021
• CPC Class Codes: H04M 1/2477 for selecting a function from a menu display H04M1/2474 takes precedence
• CPC Class Codes: H04M 1/253 Telephone sets using digital voice transmission
• CPC Class Codes: H04M 1/6033 for providing handsfree use or a loudspeaker mode in telephone sets arrangements for preventing acoustic echo H04M9/08
• CPC Class Codes: H04M 1/6505 : storing speech in digital form
• CPC Class Codes: H04M 11/06 : Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
• CPC Class Codes: H04M 11/064 : Data transmission during pauses in telephone conversation
• CPC Class Codes: H04M 11/068 : using time division multiplex techniques; integrated services digital networks H04Q11/0428
• CPC Class Codes: H04M 2203/4509 : Unified messaging with single point of access to voicemail and other mail or messaging systems
• CPC Class Codes: H04M 2250/62 : user interface aspects of conference calls
• CPC Class Codes: H04M 3/002 : Applications of echo suppressors or cancellers in telephonic connections in two-way loud-speaking telephone systems H04M9/08, echo suppressors or cancellers per se H04B3/20
• CPC Class Codes: H04M 3/42 : Systems providing special services or facilities to subscribers specially adapted for wireless communication networks H04W4/00
• CPC Class Codes: H04M 3/5307 : for recording messages comprising any combination of audio and non-audio components
• CPC Class Codes: H04M 3/533 : Voice mail systems
• CPC Class Codes: H04M 3/567 : Multimedia conference systems
• CPC Class Codes: H04M 7/0033 : Notification or handling of incoming calls by a computer
• 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
• CPC Class Codes: H04M 7/128 : Details of addressing, directories or routing tables
• CPC Class Codes: H04M 7/1295 : Details of dual tone multiple frequency signalling
• CPC Class Codes: H04N 1/00204 : with a digital computer or a digital computer system, e.g. an internet server programmed control between transmitter and receiver or between image input and image output device H04N1/32561
• CPC Class Codes: H04N 1/00206 : Transmitting or receiving computer data via an image communication device, e.g. a facsimile transceiver H04N1/00236 takes precedence

Abstract

A personal communications system enables the operator to simultaneously transmit voice and data communication to a remote site. The personal communications system is equipped with two telephone line interfaces to allow connection between two remote sites. The connection between the first remote site and the local site may operate in a voice over data communications mode to simultaneously send compressed voice and data. The connection between the local site and a second site is a voice only connection allowing the first remote site to talk to the second remote site without breaking the data communication connection between the first site and the local site. The second remote site amy be a public telephone network. The communication between the first remote site and the second remote site through the local site may also be a data communication connection, or it may also be a voice over data communication connection.

Claims

1. A communication apparatus, comprising:

data interface connected a personal computer;

first telephone line interface means for connection to a first telephone line;

second telephone line interface means for connection to a second telephone line;

telephone device means for receiving local voice signals from a local user and for conveying remote voice signals from a remote user to the local user;

full-duplex conversion means connected to the telephone device means for converting the local voice signals into outgoing digital voice data and for converting incoming digital voice data into the remote voice signals;

voice compression means connected to the full-duplex conversion means for compressing the outgoing digital voice data into compressed outgoing digital voice data and for decompressing compressed incoming digital voice data into the incoming digital voice data;

main control means connected to the voice compression means, the data interface, the first telephone line interface means and the second telephone line interface means, for

receiving the compressed outgoing digital voice data from the voice compression means,

receiving outgoing computer digital data from the personal computer through the data interface,

multiplexing and transmitting compressed outgoing digital voice data with the outgoing computer digital data to the first telephone line interface means for transmission on the first telephone line,

receiving and demultiplexing compressed incoming digital voice data and incoming computer digital data from the first telephone line interface means from the first telephone line, and

passing the remote voice signals to the second telephone line interface means for transmission on the second telephone line.

2. The apparatus according to claim 1 wherein the main control means is further operable for detecting silent periods in the outgoing digital voice data and for producing in response thereto a silence flag and wherein the main control means is further operable for transmitting outgoing conventional digital data when the silence flag indicates the absence of voice information and wherein the main control means is further operable for multiplexing and transmitting both the compressed outgoing digital voice data and the outgoing computer digital data when the silence flag indicates the presence of voice information.

3. The apparatus according to claim 1 wherein the first telephone line includes a cellular telephone link and wherein the main control means is further operable for periodically transmitting a cellular supervisory packet on the first telephone line and for maintaining the cellular telephone link over the telephone line if the receipt of the cellular supervisory packet is acknowledged within a predetermined period of time and for dropping the link over the telephone line if the cellular supervisory packet is not acknowledged within a predetermined period of time.

4. The apparatus according to claim 1 wherein the voice compression means is further operable for compressing the outgoing digital voice data into compressed outgoing digital voice data by performing the steps of:

a.) removing any DC bias in the outgoing digital voice signal to produce a pre-emphasized outgoing digital voice signal;

b.) pre-emphasizing the normalized outgoing digital voice signal to produce a pre-emphasized outgoing digital voice signal;

c.) dividing the pre-emphasized outgoing digital voice signal into segments to produce a current speech segment and a past speech segment;

d.) predicting the pitch of the current speech segment to form a pitch prediction;

e.) calculating the gain of the pitch of the current speech segment to form a prediction gain;

f.) reconstructing the past speech segment from a compressed past segment to produce a reconstructed past segment;

g.) finding the innovation in the current speech segment by comparing the pitch prediction to the reconstructed past segment to produce an error signal;

h.) determining the maximum amplitude in the current speech segment;

i.) quantizing the error signal using a code book generated from a representative set of speakers and environments to produce a minimum mean squared error matching the form of an index into the code book; and

j.) recording the pitch prediction, the prediction gain, the maximum amplitude and the index into the code book in a packet as the compressed outgoing digital voice data.

5. The apparatus according to claim 1 wherein the main control means is further operable for passing the outgoing computer digital data along with the remote voice signals to the second telephone line interface means for transmission on the second telephone line.