Method and apparatus for allowing ordinary telephones to connect to a data network

0001METHOD AND APPARATUS FOR ALLOWING ORDINARY TELEPHONES TO CONNECT TO A DATA NETWORK

0002Technical Field

0003The present invention relates to a method and an apparatus for connecting ordinary telephones to data communication networks.

0004Background

0005The use of the Internet, and of other Internet Protocol (IP) type networks is increasing rapidly. However connections to such networks requires fairly expensive hardware, such as a Personal Computer (PC).

0006Telephones are generally available everywhere and they are easy to use. There is therefore a desire to provide an interface which will allow the use of an ordinary telephone for connecting to IP networks, even though it will not be possible to utilize all the possibilities offered by such a network, using only a telephone.

0007Summary of the Invention

0008It is an object of the present invention to provide a connection from an ordinary telephone to a data network without the need for additional hardware.

0009It is another object of the present invention to provide a connection from a telephone to a data network which is inexpensive compared to the solutions currently available, and easy to install and maintain.

0010These will be particularly useful for TCP IP networks, which are most commonly used for data communications today.

0011The objects are achieved by the present invention by providing an adapter between the telephone and the data network connector which carries out the following functions:

0012- termination of the data protocol used - responding to incoming telephone calls over the data network

0013- translation of off-hook positions and digits dialled to configurable call requests that are handled by the Internet telephony system.

0014- translation of incoming calls from the Internet telephone system into dial-tone and on/off hook positions to establishment of a call

0015- bidirectional translation of speech data according to the appropriate coding.

0016- reconfiguration of the Reg., CH and SC functions from the data network. The adapter may be implemented as a microprocessor and placed inside the telephone housing. The ordinary telephone jack is then replaced by the data network connector.

0017The solution according to the invention offers the following advantages:

0018An inexpensive way of connecting an ordinary telephone to a data network, such as a TCP/IP network and to an Internet telephone system is provided.

0019The adapter is configurable from the data network and may therefore be adapted to the changing requirements on speech coders/decoders, Internet telephony registration procedures, call request and call out procedures.

0020The equipment required according to the invention is easy to install for the user, as everything may be assembled and configured by the manufacturer before installation.

0021Brief Description of the Drawings

0022Figure 1 is a schematic drawing of a data network to which telephones are connected through adapters according to the invention;

0023Figure 2 is a schematic drawing of a telephone connection to a IP network through an adapter according to the invention;

0024Figure 3 is a flow chart of the activities earned out when an outgoing call is being set up;

0025Figure 4 illustrates schematically the communication in the adapter in the set-up phase of a call; Figure 5 illustrates schematically the communication in the adapter while a call.is being made;

0026Figure 6 shows the connection of a mobile or cellular telephone to a data network according to the invention.

0027Detailed Description of Embodiments

0028Figure 1 shows an data network 1, to which a number of subscribers are connected. In this figure, and in the following discussion, the data network is taken to be a TCP/IP network, as this is the most commonly used network protocol today.

0029In Figure 1, two telephone subscribers 3 are connected to the network through adapters 5 according to the invention. The adapter 5 may be comprised in the telephone housing or anywhere between the telephone and the IP network. If the adapter is integrated in the telephone, the telephone may be connected to the IP network in the same way as a computer. Some of the ordinary telephone functions could then be omitted.

0030In addition any number of computers 7, for example personal computers or workstations, connected to the IP network either via leased lines or via modem, or in any other way common in the ait.

0031Through the adapter 5 according to the invention, calls may be established from any subscriber 3 to any other terminal 3, 7 in the network.

0032Figure 2 shows a telephone 3 ' connected to an IP network 1 ' through an adapter 5 ' according to the invention.

0033The adapter 5' comprises the following units:

0034An input buffer IB and an output buffer OB, which buffer the audio packages to be transmitted on the network and received from the network, respectively. A Speech Coder/Decoder SC, which encodes speech so that it can be transmitted on the IP network, which is packet switched, and decodes incoming packets containing speech, so that they can be received in the telephone.

0035A Call Handler CH, which translates dialling and hook positions into configurable call requests that are handled by the Internet telephony system, and translates incoming calls from the Internet telephony system into dialling-tones and establishes calls

0036A register block REG, which stores information about the Internet telephony A number. This number may be configured by a user using the telephone or from the

0037IP network.

0038A TCP/IP stack S for communication with the IP network

0039A Central Processing Unit CPU which controls the functions of the other blocks in the adapter 5.

0040Figure 3 is a flow chart of the actions performed when a telephone subscriber connected to the IP networks by an adapter according to the invention, wants to make a phone call.

0041Step S3 1: The user lifts the hook and an off-hook signal is transmitted to the Call Handler CH. The signalling is done in a way common in the ait, for example by Dual Tone Multi Frequency (DTMF) signalling or voice control between the telephone and the adapter. If the adapter is implemented as part of the telephone, an I/O circuit in the adapter connects the keyboard directly to the CPU of the adapter.

0042Step S32: The Call Handler CH retrieves the A number from the register REG.

0043Step S33: The Call Handler CH signals to the TCP/IP stack that a connection through the IP network is requested. Step S34: Signalling takes place between the TCP/IP stack and the network in a way common in the ait, for example, in the way defined in the H.323 protocol.

0044Step S35: When an OK has been received from the B subscriber, the connection from the A subscriber to the B subscriber is set up through the network.

0045Figure 4 shows the connections between the units in the adapter that are used in the set-up phase of a call. The adapter is identical to the one shown in Figure 2. The Call Handler CH detects the off-hook state of the telephone and requests the A number from the register REG. The Call Handler then requests the TCP/IP stack to set up the connection to the network in the way common in the ait.

0046Figure 5 shows the path taken by the speech through the adapter after the connection has been set up. The adapter shown is identical to the one shown in Figure 2.

0047First, the outgoing data is stored in the input buffer IB. When the input buffer IB is full, the data is forwarded to the signal coder/decoder SC via the central processing unit CPU. The signal coder/decoder SC compresses the data and forwards it via the central processing unit CPU to the TCP/IP stack, where the header field is added, before the packet is transmitted to the local area network. Through the IP network the data packages are transmitted in the way common in the ait.

0048When a phone call is received, the Call Handler CH verifies that the call is intended for the subscriber connected to this adapter and initiates the set-up of the call through the TCP/IP stack. The connections are similar to the ones shown in Figure 5, except that the output buffer OB is used instead of the input buffer IB. How to implement this is known to the skilled person.

0049A phone call is ended when one of the users replaces the hook on the telephone. Figure 6 shows a possible connection between a mobile, or cellular, telephone ! 1 and a data network 13 according to the invention. The mobile telephone 11 comprises the standard telephony functions 15, an adapter 17 according to the invention, that is, with similar functions to the adapters 5, 5' shown in the previous drawings, and a radio communication unit 19. The connection to the network is a radio connection, and thus a communication unit 21 is needed at the entrance to the network as well.