DE2917330A1 - DIGITAL TERMINAL DEVICE FOR USE IN A DIGITAL DATA COMMUNICATION LINE NETWORK AND METHOD FOR CONNECTING TWO TERMINAL DEVICES IN A DIGITAL DATA NETWORK - Google Patents

Description

L M ERICSSON PTY.LTD., Riggall Street, Broadmeadows, 3047 Victoria, Australia

Digital terminal device for use in a digital data communication line network and methods of connecting two terminal devices in a digital one Data network

The invention relates to a digital terminal device for use in a digital data communication line network, those for deriving timing signals from the line network, those for deriving of timing signals from digital data received from the line network is set up to generate a local timing signal to control the data bit rate of the terminal,

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Office Bremen / Bremen Ofice: P.O. Box / P.O. Box 10 7127 Fcldstrasse 24, DCoJO Bremen 1 Telephone: (0421) "7 40 44 Telecopier / Telecopier: Rank Xerox 400 Ti'lcjjr. / Cables: diagram Bremen

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Accounts Bremen: Bremer Bank, Bremen (BLZ 290 800 10) 100 1449 Deutsche Bank, Bremen (Sort code 290 700 50) U12002 PSchA Hamburg

Munich Office: P.O. Box / P. O. Box 14 0108 Schlotthauerstraße 3

D-8000 Munich 5

Telephone: (089) 65 23 21

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and a method for connecting two terminal devices in a digital data network, wherein the terminals either normally at different data bit transfer rates or at same bit data transfer speeds work, but connected via a data link on the network are that compared to the terminals with a lower data bit transmission speed is working.

The invention thus relates to digital data communication line networks, whereby different parts of the network have different data transmission

■ t speed capabilities or limits to the »
g wise. In particular, the invention relates to

$ a method and apparatus for connecting

§ of terminal devices in such a

5; Establishment if either the one in question

h terminal devices normally in case of different

| t borrowed data speeds or working them over

; | Data links are to be connected,

J; which are normally used at different data speeds

■ J work.

For example, the invention is particularly useful in digital

Telephone facilities, however, are of course not limited to just these as they are just as good at others digital facilities can be applied.

The need for the invention arises for a variety of reasons. E.g. with a large digital telephone device a higher-level exchange with a first relatively high data bit

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Speed work with most of their dependent digital phones as these are relative are close to the exchange. Bandwidth limits are then imposed by the connecting medium, the cable not on. Nonetheless, this exchange may also have some dependent telephones running on the End of long transmission lines are or to this through dependent links such as E. a radio system or a satellite system with connected data modes are coupled. To maintain the bandwidth in such cases it can be for the distant, dependent Telephone may be necessary with a somewhat reduced data bit transmission speed to work according to the first bit rate.

In another, similar example, the need for the invention arises in that a Telephone connected to a first exchange at a relatively high first data bit rate works, with a phone connected to a second exchange and operates at the same speed, is to communicate via a data link of slower speed capacity. Similarly, it may be necessary be, with a slow speed phone connected to a remote exchange is to communicate with a high speed data link available. Here would again arise the need for the present invention.

So the problem always arises whenever two telephones are connected to different data speeds.

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are working, are to be connected to each other _/ or if two telephones are connected to. work at the same data speed must be connected via a slower data transmission link.

A simple and obvious way of solving this problem The solution to this is to change the terminals (telephones) that operate at the slower data-bit transfer speeds work on the pipe network with the help of separation units that are at the entrance to first Switching nodes or final exchanges are connected to adapt. Such separation units would be the digital ones Convert data back into analog data and then convert the analog information into the appropriate digital one Encrypt bit rate. This solution would be relatively expensive and is still not digital To use high security communication systems, in which encryption devices at the terminals used to ensure that the data does not pass during its passage through the wire network clipped and decoded. In such security systems it would be necessary to connect to the separation units to decipher, which would lead to further considerable increases in the cost of the system and the Security would be degraded.

The object of the invention is therefore to provide an improved method and device for combining from terminal devices in a digital data line network, whereby terminal Devices operate normally at various data bit rates or through a data link with different data bit speeds

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can be connected to the terminals.

The object is achieved according to the invention that digital, terminal devices for use in a digital Data communication line network are used, which are characterized in that this device either responds to a received code word or the bit rate of incoming data is arranged so that data with a different Bit speed are sent at appropriate times.

The method according to the invention is thereby aeichnet from that the method comprises the following steps: Discover at a switching point in the network that a first terminal has established a connection with a second terminal. Determination with the help of a Processor at the switching point whether this second terminal for normal work at a different Data transmission speed to the first terminal is set up and whether this connection is via a data link takes place in the network, which in operation on a lower data transmission speed than the normal bit rate of one or both terminals is limited and sending a digital Bit stream to one or both of the terminals to cause them to occur during this connection at the lowest of the usual data bit transmission speed the terminals and the data link to work.

The invention thus relates to a method

for connecting terminal devices in a digital

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Telephone line network where either the terminal devices usually operate at different data speeds or use them through data links should be connected in the line network, normally at different data speeds work. This method concerns, first, the determination of normal data bit transmission rates of two terminals to be connected as well as the normal data bit rate of the or any data link through which the connection should take place by processor means at a switching point in the line network. If there is any difference is found in the normal data bit rates, the processor invokes a procedure send a digital bit stream to one or both of the terminals to cause the terminals to in the course of the connection at a uniform data speed, corresponding to the lowest normal data bit speeds of the terminals and the data transmission link. A Phone that is received for working at different data speeds according to a Digital bit stream is set up at the new speed or to a digital code word, is also described and claimed.

Further features and advantages of the invention emerge from the claims and from the following description, in which an exemplary embodiment is explained with reference to the drawing consisting of three figures. It shows:

Fig. 1 is a schematic block diagram of a simplified line network comprising the device according to the invention includes;

BOEHMERT & BOEHMERX

Fig. 2 is a circuit diagram of a digital

Telephone according to the device according to the invention; and

Fig. 3 is a timing diagram of data waveforms; those in the telephone of FIG. 2 currently. are.

According to Fig. 1, the simplified device consists of a digital telephone A, which is at a switching point or Exchange point SP is connected and another digital telephone B, which is also connected to SP is. Of course, many more telephones will be connected to the exchange point SP in practice. The need for the device according to the invention can best be explained by the fact that the following Procedure for establishing a connection between digital telephone A and digital telephone B. is described. It is assumed that telephone A is normally operating at 32 KHz and telephone B is operating only at 16 KHz, e.g. due to bandwidth restrictions on the connection between telephone B and the Switching point SP. A connection is now established in the following way:

It is assumed that telephone A originates the call. The line signals between A and SP and between B and SP are in the form of digital codes that are recognized by SP through constant monitoring of the subscriber lines. This is the normal process. The monitoring of the lines can be carried out in different ways, for example by multiple execution of one type of code receiver on the 32 KHz telephones and another type code receiver on the 16 KHz telephones or, as in the case of the invention

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according to the device, in which the same code receiver is used for all lines, but the line signals are selected so that a bit stream from telephone B has the same meaning for the code receiver as a bit stream from telephone A.

When the signal from the register has been received in SP, the processor (not shown) in SP fraat a B-subscriber identification table. This table shows that phone B is limited to 16 KHz data rate transmission. The switching point SP calls telephone B by sending a ringing signal to telephone B at 16 kHz. Telephone B's answer code is transmitted to SP. The answer code from telephone B normally causes the call to be put through. Nevertheless, in the device described, the data transmission speed to telephone A is changed to 16 KHz before the SP is put through as a result of the "B-subscriber" identification table. The data transfer rate from telephone A to SP is subordinated to the data transfer rate which is transmitted from SP, since in this device data is processed as data biphasic data and the time setting is adopted on the remote telephones. The change in the data transmission speed at SP from telephone A is realized in SP by monitoring the bit stream from telephone A. At this point, put through takes place. It should be obvious that a plurality of different switching points or exchange SP may occur in the supply network between the phone A and phone B. In fact, with a

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another situation where phone A and phone j-

B at the same data transmission speed; work, but a link between the two when exchanging that for the connection between phone

A and B is necessary with a lower data over- ΐ

carrying speed works, and as a result j.

of which for the purpose of the connection both the telephone A i

as well as telephone B for the lower data- 1

transmission speed must work .. |

2 shows a simple block diagram |

of a digital telephone that has circuitry |

to the phone at two different digital data |

To make transmission speeds usable. ff

For the purpose of the invention a telephone is needed, |

which either responds to a code word that is given by g

an exchange is sent or on the bit Uber- i

transmission speed of the incoming data to part 5,

S hair dryer. In this particular embodiment of the R

The device according to the invention is provided that f

I the TeIefönapparat to the data transfer I

speed of the incoming data. Sj

The main parts of the digital telephone of Fig. 2 have f-

a line connection circuit 1, which connects the four-wire telephone line from the inner telephone circuit separates and performs the necessary amplification and shaping of the signals in both transmission directions, a time-keeping and diphasic modem circuit 2, the time phase from the incoming bit stream regenerated to provide a timing signal on link 2a, outbound, non-zero-going NRZ) data into diphasic, modulated data and an-

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converts incoming diphasic data to NRZ, a timing capacitor 3 with associated resistance 3a, which are required by the timer circuit 2, the codec 4, the analog / digital and digital / Performs analog conversions with the help of delta modulation technology and the amplifier and filter unit 5, which separates the transmitter 7 from the receiver 6. The telephone also has a pre-generator 8 which converts the digits from the keyboard 9 into a serial digital pattern, a code receiver 10, which receives codes such as calls and ringing, to the ringing unit 12 via a ringing generator circuit to apply. SW1 is a toggle hook shown in the closed position.

The details described above compose a standard digital telephone.

Additional components, which are described below, are necessary for the telephone to work make relying on two different incoming data transfer speeds to adjust. In this preferred embodiment of the invention The data transmission speeds taken into account are 32 and 16 KHz.

In Fig. 3 are the waveforms for the 32 KHz data transmission rates, indicated by the reference numeral 20 and the waveforms of the 16 KHz data transmission speeds by the Reference numeral 21. In the respective groups 20 and 21, the waveforms 31, the system timing signals, which are shown for reference. The waveforms

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are typical diphasic modulated data bit streams. From these waveforms it can be seen that at 32 KHz the pulse periods consist of t and 2t, while at 6 KHz they consist of 2t and 4t (t = 15.625 / u see.). In this preferred embodiment, the frequency is ier measured incoming data and used the frequency of periods t and 4t to determine the presence of 32 KHz and 16 KHz accordingly.

In Fig. 2, the flip-flop 13, the inverter 14, the gates 15, 16, 17 and 18, the local oscillator 19, the 3-bit binary counter 29 / the gates 21, 22 and 23 and the RS flip-flop 24 the frequency-measuring Circuit shown as block 40. The transistor 25 controlled by the flip-flop 24 turns the timing resistor RT2 on or off, which makes the timing circuit that is shown as block 41, is repaired based on the incoming data transmission speed to adjust. In Fig. 3, the corresponding waveforms 33 are formed by using the waveform 32 in the Flip-flop 13 (Fig. 2) is divided by two. The purpose of this approach is to phase how shown by the patterns 34, 35 and 36 in groups 20 and 21, in order to measure the Simplify data transfer speeds. The phases are brought out through gates 15, 16 and 17 in FIG.

During the waveform 34 phase, gate 18 is open, by a number of timing pulses from the local oscillator 19 to reach the binary counter 29 enable de * · beforehand through the waveform 35 phase

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has been deleted. The waveform 36 phase is transferred the state of the binary counter 29 on the RS flip-flop

The measured frequencies will be t, 2t and 4t. When the local oscillator 19 operates at 104 KHz (waveform 37) works, a frequency of t will let one or two time pulses through to the binary counter 29, a frequency 2t becomes a registration of 3 or 4 pulses and a frequency of 4t becomes a registration of 6 or 7 pulses. The waveform 38 shows the data coming from the oscillator 19 into the counter 29.

If 1 or 2 counting pulses have been registered in the binary counter 29, the gates 21 and 22 will set the RS-Flip-F] op 24 and if 6 or 7 counting pulses have been registered in the counter 29, the gate 2 3 becomes the flip-flop 24 reset. All other counting pulses in the binary counter 29 are ignored. So when a period t is measured, the resistor RT2 is connected in parallel with RT1 by means of the transistor 25 and the RS flip-flop 24, which enables the extraction of counting pulses at 32 KHz. If a period of 4t is measured, the flip-flop and transistor will turn off the parallel RT2, thereby allowing the extraction of a timing pulse rate of 16 KHz.

The code generator 8 has a control input from the RS flip-flop 24, whereby the signaling Codes can be made by the phone regardless of the time pulse rate. This simplifies the code reception in the end exchangers.

The local oscillator 19 is a free-running LC

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or an emitter-coupled oscillator which requires plus or minus 7.6% precision if it is to be used in the timing device shown. A higher oscillator frequency with a longer counter and a more complex decoding method also allows the use of an oscillator with a lower accuracy. It is believed, nonetheless, that plus or minus 7.6% should not be difficult to achieve within the required temperature range. It should be apparent to those skilled in the art that the invention is not limited to the preferred embodiment described above. For example, it is not restricted to digital telephone systems; other communication systems can also be set up in such a way that they can accommodate the device according to the invention. The output devices can also be set up in such a way that they can implement more than two different digital bit transmission speeds. As far as switch points or exchange points of the system are concerned, the only need for the local processor is that it be programmed to determine the limits of digital data transfer rates to the end devices with the intention of making a connection .len. In other words, the exchange processor only queries a look-up table to determine if any data links or end devices served on a link are in any way limited in data bit rate.

The in the above description, as well as in the

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Features of the invention disclosed in the following claims can be used individually as well as in any Combinations are essential for realizing the invention in its various embodiments be.

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.: '.. ' .. ''. ^:: I '. File: L 423

REFERENCE37, ICHENLI3TE
(LIST OF RSFiRETJGE NUMERALS)

1 line connection circuit 1 2 biphasic mode circuit ? ■ 5 timing capacitor, 3a resistor q. Codex 5 filter / amplifier unit 5 6 recipients 6th 7 channels 7th 8 code generator 8th 9 keyboard q 10 code receivers 10 11 Bell circuit 11 12 blade unit 1? 13 flip flop 13th 14 inverter 14th 15 goal 15th 16 goal 16 17 goal 17th 18 goal 18th 19 local oscillator iq 20 wave spectrum of the 32 KHz data (Fiq. 3) PO 21 wave spectrum of the 16 KHz data (Fin. 3) P1 22 gate 22nd 23 gate 23 24 RS-FH p-Floo 24 25th ? 5 PPi 26th 27 27 28 ?8th 29 binary counter, 3 bit 29 30th 30th

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31 waveform, Fig. 3-32 KhZ and 16 KHz data 31 3? dto. 32 33 dto. 33 34 dto. 34 35 dto. 35 36 dto. 36 37 dto. 37 38 dto. 38 39 39 ^ O block of 13, 14, 15, 16, 17, 18, 19, 29, 21-23, 24 40 41 block, timer circuit 41 4-2 42 43 43 44 44 45 ^ 5 46 46 47 47 48 48 49 49 50 50 51 51 52 52 53 53 54 54 55 55 56 56 57 57 55 58 59 59 60 60 61 61 62 62 63 63 64 64 65 65

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A digital telephone?

B digital telephone

SP switch point; Exchange point

2A connection f

NRZ Non-Return-To-Zero-Date \;

SW1 switch hook |

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Claims (4)

EXPECTATIONS η) Method for connecting two terminal devices (A, B) in a digital data network, the terminals either normally operating at different data bit transmission speeds or at the same data bit transmission speeds, but via a data link in the network are connected, which works compared to the terminals with a lower data bit transmission rate, characterized in that the method comprises the following steps: Discovering at a switching point (SP) in the network that a first terminal (A) is connected to a second Terminal (B) has received; Determination with the aid of a processor at the switching point (SP); whether this second terminal is set up for normal work at a different data transmission rate to the first terminal, and whether this connection is made via a data link in the network which, during operation, is set to a lower data transmission rate than the normal bit rate of one or both terminals is limited _; and sending a digital bit stream to one or both of the terminals to cause them to occur during that connection at the lowest of the 8098A5 / 09SS BOEHMERT & -BPEHMERT usual data bit transmission speed Terminals and the data link to work. 2. The method of claim 1, wherein the network is a telephone line network and the terminals are digital telephones which are controlled by a switching point in the line network so that the Clock signal is derived from digital data sent by the switching points above the telephone are characterized in that the step of determining the relative data speed of the first (called user) and the second (called user) terminal (A, B) and the data link by using a processor to query a called subscriber identification table for the purpose Determination of the normal data bit transmission speed capabilities of the called subscriber and any data link required for this connection and comparison of those obtained in this way Information from this identification table for normal data processing speed relevant information of the calling subscriber, such as from the information received at the switching point digital data can be seen when the calling party starts a call, the digital bit stream, to a telephone to change the data bit transfer rate from data of the there is a new bit transmission speed that the Telephone to work at the new data transfer speed cause .. 3. Digital terminal device for use in £ 09645/0965 BOEHMERT & BOEHMERT a digital data communication line network, which is used to derive timing signals from the line network received digital data is set up to a local timing signal for controlling the Bring out data bit rate of the terminal, characterized in that this device to answer either to a received digital code word or to the bit rate of incoming data hin is set up so that data with a different bit rate to corresponding Times are sent. 4. Digital terminal device according to claim 3, characterized in that the device for answering is set up on the bit rate of incoming data, the device having a frequency measuring Circle (40) for determining the data rate of incoming data and a dem Frequency-measuring circuit subordinate, timing circuit (41) for switching between two different states that correspond to two different speeds of incoming data, creating a clock derivative Circuit (2) connected to timing circuit (41) for deriving the timing signal is caused from the special, incoming data »includes. 909846/0966