CONNECTION OF A COMPUTER TO A TELEPHONE EXCHANGE
TECHNICAL FIELD 5
The present invention relates to the connection of a computer to a telephone exchange and more particularly to a private branch exchange having a computer connected as an extension for telephone purposes. ^
STATE OF THE ART
Computer networks in the form of internet and intranets are in widespread use and the possibility of transmitting voice over computer networks such as the internet has ^ become more and more popular because of the low price on using the internet. Many companies also have intranets or local computer networks for communication between computers in the company.
Many computers today are also equipped with 20 loudspeakers, microphones and software for using the computer as a telephone. Such types of software include Webphone and Cooltalk.
WO96/20553 is mainly concerned with a system of transmitting voice mail and electronic mail messages in a 25 computer network. It does also describe setting up of telephone calls via the internet. It is however not concerned with setting up telephone calls to a computer.
In a Brochure "An introduction to distributed multimedia networks", by Harvey Kaufman, Netspeak Corporation, a telecommunication system is shown including telephone exchanges in the form of private branch exchanges (PBX) which are interconnected both by a public switched telephone network (PSTN) and by computer networks to computers. They are connected to the computer via gateways. This document describes the setting up of a telephone call from a computer to an ACD center (Automatic Call Distribution) that might be incorporated into an exchange. The computer is here probably connected to this exchange via a modem and the public switched telephone network PSTN, and not directly to the exchange via a computer network.
The telecommunications standard ITU-T H.323 describes different protocols for conversion of speech to data packets ^ in a gateway and vice versa for use in communication between computers and telephone equipment.
The Swedish patent application No. SE 9602918-6, filed 2 Aug. 1996, which is identical to U.S. provisional application "Method and Arrangement for Connection Between a 50 Computer Network and a Telecommunication Network", filed Aug. 12, 1996, describes how two private branch exchanges can use the internet for setting up compressed voice calls between them, each using a modem connected to the backplane or switch core of the PBX. 55
Swedish patent application No. SE 9602212-4, filed 4 Jun. 1996, discloses an exchange in a telecommunication network to which a computer is connected via a modem. Calls made to the telephone number associated with the modem are re-routed to a telephone server, for compression, go packing into packets and contacting of the computer via internet. The connection between the exchange and the computer is a telephone connection. In this case telephone signals are packed into data packets that are then sent on a normal telephone line. 65
Swedish patent application No. SE 9604409-4 filed 29 Nov. 1996 discloses a modem which multiplexes telephone
signals and data packets on a telephone line so that a user having his computer connected to the PSTN can talk on the telephone while at the same time using the computer via this sole telephone connection.
Swedish patent application No. SE 9700152-3, filed 21 Jan. 1997 describes a computer that controls a cordless telephone connected to an exchange.
SUMMARY OF THE INVENTION
Multimedia PCs (personal computers) of today have the necessary hardware to handle voice. A lot of software is becoming available, which provides telephone functionality to those PCs. Many companies have multimedia PCs on the desks, but they cannot be directly connected to a PBX (Private Branch Exchange), and the PBX features and resources are not available to the PCs.
Thus the present invention concerns a problem of how to connect a computer to an exchange for use as a telephone extension, when both the exchange and the computer are connected to a computer network and the computer comprises a telephone function.
This is solved by registering, in the exchange, the computer as a telephone to which calls can be made and allocating a telephone number to the computer, by setting up, between a network connection device of the exchange and the computer via the computer network, at least one traffic channel for receiving speech signals. The network connection device receives data packets containing telephony from the computer over said traffic channel and removes a signal structure suitable for telephony over the computer network from the content of the data packets. The object of the invention is thus to obtain an exchange, a telephone system comprising such an exchange and a method for connecting a computer to the exchange as an extension for use as a telephone, when both the exchange and the computer are connected to a computer network and the computer comprises a telephone function.
This object is achieved by an exchange and a telephone system, where the exchange comprises a switch core, a switch control means responsible for setting up connections between users of the exchange and at least one first network connection device connected between the switch core and the computer network. The computer comprises a telephone function and has a computer network address. One network connection device in the exchange registers the computer as a telephone to which calls can be made in the switch control means and sets up, via the computer network, at least one traffic channel between the exchange and the computer for sending speech signals. The network connection device applies a signal structure suitable for telephony over the computer network to speech signals received from the switch core in order to produce data packets containing telephony, which speech signals are intended for the computer. The network connection device sends the data packets containing telephony to the computer over the traffic channel. The switch control means allocates a telephone number to the computer.
This object is also achieved by a method having the steps of registering, in the exchange, the computer as a telephone to which calls can be made and allocating a telephone number to the computer,
setting up, via the computer network, at least one traffic channel between the exchange and the computer, for sending speech signals,
applying, in the exchange, a signal structure suitable for telephony over the computer network to speech signals
intended for the computer in order to produce data packets containing telephony, and sending the data packets containing telephony to the
computer over said traffic channel. The object is also achieved by an exchange and a tele- 5 phone system, where the exchange comprises a switch core, a switch control means responsible for setting up connections between users of the exchange and at least one first network connection device connected between the switch core and the computer network. The computer comprises a 1Q telephone function and has a computer network address. One network connection device in the exchange registers the computer as a telephone to which calls can be made in the switch control means and sets up, via the computer network, at least one traffic channel between the exchange and the computer for receiving speech signals. The network con- 15 nection device receives data packets containing telephony from the computer over said traffic channel and removes a signal structure suitable for telephony over the computer network from the content of the data packets. The switch control means allocates a telephone number to the computer. 20
The object is furthermore achieved by a method comprising the steps of:
registering, in the exchange, the computer as a telephone to which calls can be made and allocating a telephone number to the computer, 25 setting up, via the computer network, a traffic channel between the exchange and the computer, for receiving speech signals, receiving, in the exchange, data packets containing telephony from the computer over said signalling channel or over a traffic channel; and 30 removing a signal structure suitable for telephony over the computer network from the content of the data packets. A traffic channel or the signalling channel when used as a traffic channel are not channels in the ordinary sense. They preferably use UDP (unreliable datagram protocol). The 35 channels then are connection-less type of connections. These channels do thus not have any relation to channels in time slots and channels of that type. The switch control means does however treat them as these ordinary traffic channels. 40
The invention has several advantages. By connecting the computer to the exchange as a telephone extension, the computer can use all of the resources available to a normal extension, such as conference connections, voice mail systems, call-back functions etc. 45
The invention has several advantages, where one is that companies having a private branch exchange can see to it that a computer can be used as a telephone for example at locations where there are no telephone sockets or to connect temporary workers having a computer but no telephone to 50 the exchange.
One furthermore gains the advantage of using the monitoring functions present in the exchange in monitoring traffic to such an extension.
Another advantage is that the computer can use all of the 55 resources available to a normal extension, such as conference connections, voice mail systems, call-back functions, possibility to connect calls via an operator and possibility of connecting to trunk lines.
The invention will now be described in more detail with 60 reference to preferred embodiments and to the enclosed drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a block schematic of a telephone system 65 according to the invention comprising a telecommunication exchange connected to a computer via a computer network,
FIG. 2 shows a block schematic of a computer network connection device in an exchange,
FIG. 3 shows a flow chart of a method for connecting the computer as an extension of the exchange,
FIG. 4 shows a flow chart of a method used by the exchange for sending telephone signals to the computer over the computer network, and
FIG. 5 shows a flow chart of a method used by the exchange for receiving telephone signals from the computer over the computer network.
DETAILED DESCRIPTION OF PREFERRED
EMBODIMENTS
In FIG. 1 is shown a telephone system according to the invention comprising a telephone exchange PBX 10, for example in the form of private branch exchange, which is connected to a computer PC 50 by a computer network 14, which network is, in this embodiment, an intranet. A DNS (Domain Name System) server 16 is also connected to the intranet 14.
It shall be understood that the system could include more telephone exchanges, each connected to the intranet. The computer network is also not limited to an intranet but also internet is possible as well as various types of local networks or combinations of intranet and internet so that exchanges connected to the internet can get connected to the intranet of a company. The system is also not limited to private branch exchanges.
The exchange 10 PBX comprises a switch control means 42 connected to a switch core 40 and to a network connection device 44, where the network connection device 44 is connected between the switch core 40 and a gate 56 for connection to the computer network 14. The switch core 40 is connected to a first extension 52 (shown outside the exchange). The extension could also be replaced by a subscriber in a public switched telephone network (PSTN) who gets connected to a private branch exchange via said PSTN. What happens with the computer and the exchange is that the computer gets in contact with the exchange so that it can act as an extension of the exchange, to which normal telephone calls can be made. In order to do this a traffic channel is set up between the computer and the exchange via the intranet 14. This can be very advantageous in that companies that have a private branch exchange can see to it that a computer can be used as a telephone for example at locations where there are no telephone sockets or to connect temporary workers having a computer but no telephone to the exchange.
The exchange 10 can comprise several network connection devices 44, where each could be used for different computers or one handles several computers connected to it. The main part of the description and the figures will however only be limited to one network connection device for simplicity.
In FIG. 2 is shown a network connection device 44 according to the invention. The network connection device 44 comprises a signal shaping means 22 connected to the switch core of the exchange, a signal processing means 24 connected between the signal shaping means and the gate and a local control means 20 connected to the switch control means as well as to the signal shaping means 22 and the signal processing means 24. The network connection device 44 is preferably realised in the form of a processor having various memories and registers connected to it.
FIG. 3 shows a method for initially connecting a computer to an exchange and registering it as an extension.
|
