Connecting unit for a ring bus.

23ο ?? £ in! ................ ........ Γη

ii 1 In

in 'CONNECTION DEVICE FOR A RING BUS.,'!. · in

The invention relates to a method and apparatus I. et .......

5 telecommunication system for the transmission of information

Between terminals commonly connected by a jringbuss, an adjustment in the transition between the bus and respective terminal, where the terminals may assume different logical t: .l- | stander.

10 -; j · JILDA prior art are commonly used devices with a simple, amplification function, i.e., the signals pass straight through lenheten and receives only correction of the signal shape in relation

Ί 'In

; To distortion of the wire. As an example of such, I

15 | connecting device referred to a circuit made of EXAR integration

IgrATED SYSTEMS INC, type XR-C277. The circuit has a regenerer- ι_ ·

Iende amplifier function utilized in PCM systems.

! '

One problem with devices of the prior art is that a * t 'of 20 defects, eg. in the form of an interruption of one of the terminals

I · In

connected to the ring bus, also causes a breakdown of the entire bus, and in the case of a series bus this stops all traffic on the bus. The device according to the invention, which is characterized by paténtkraveneløser this problem in that! 25 each of the terminals is connected to the bus via a connecting device. The terminals can take different states in relation to In

bus. With power supply unavailable, the terminal In

ii not connected, .and can either receive or monitor datastrømr but on the bus. With the power connected, but in SLØYFEFRAKOBLET-! 30 condition is terminal not connected to the bus, but-can monitor data stream. In PASSIVE condition is terminal j connected to the bus for receiving the data stream, and terminalp one can also interrupt the data stream if it is caused to, in active. In the ACTIVE condition the terminal has access to the bus 35 and also the initiative in the traffic in progress. ,.

ij

Connectivity Your device functions as a switch between the ring bus -, 'j

and the terminal so that when the terminal is not force fed, yesterday. i, I

Idatastrømmen on the bus directly through the device, the recently- ...

...

'2:01 \ · mentioned acts as a pure amplifier, while when the power is supplied

terminal and is eg. in ACTIVE condition, you are! IN

1 | in pmkobling place in the unit preventing escape key when ru bus '5 (one passing through the device, the power · instead fit · · ..' ii.

leads through the terminal through the output transformer ii unit and onto the bus. · Li ·! In the terminal's docking device interworking 10 · Transceive, for receiving information: from the device for analysis. The signal on the bus also continues' straight through the device, which has an amplifier function.! "in

The terminal is waiting for connection to the bus until it has.

in.

received a particular code combination in the incoming data 15 'stream. When this combination is received terminal sends a blocking signal to the connection device and interrupts thereby the data stream through this. In accordance with the received

• J

information transmitting terminal then the data out to the bus via the unit's output transformer. The information on bus 20 now flows through the terminal and may be affected by the latter in

S

Blocking signal is also triggered by power interruptions.

The purpose of the device of the invention is thus to obtain a security function against faults, said function 25 maintains data flow through the ring bus although etJ

breakage should occur in one of the terminals connected Tilje j bus. 1 In

'J S

The inventive device will now be described in detail 30 by means of an embodiment, reference being made to the j accompanying drawings, in which:; ·. · '. . In 1 ''!

Fig. 1 is a diagram of a system in which the device is incorporated, and j | 35 · 'j! FIG. 2 is a principle diagram of a connecting unit j of the invention and indicates said · transmit and receive logic in the terminal for clarity. in Μ; '' 3; j .....

As will be apparent from FIG. 1 is a number of terminals TI - m- T6 every 'connected to a common ring bus RB via a connection j' unit CU. The bus is enkeltretnings-series type, which '5 j means that data flows only. through the connecting unit in one 'direction.

According to FIG. 2 device receives at the input a / b of a transformer TRI it on the bus circulating information. a | 10 ·. in·.'··

output transformer TR2 sends information to the bus RB

via an output d / d. Constant power supply to unit j obtained in known manner by means of a zener diode Z, connected •! in

between the center taps on inngangstransformatorens TRI primary; reeling and utgangstransformatorens TR2 secondary. IN

15 In

• if

Between the transformers connected circuit logic utilized | ' 'As amplification or switching logic required. The j includes the following: i '<··. a regenerative differential amplifier Fl, .eksempelvis! in: 20 in 'made by EXAR INTEGRATED SYSTEMS, INC type XRC277 ,. which | . contains a clock signal unit and a regererativ amplifier! for regenerating incoming data, as well as the generation of synchronizing signals for the terminal transmitting and receiving ji logic A, one amplifier F2 for distributing to the input of! ' ! 25 'terminal receiver of data signals som.kommer from the bus. ; regenerated in the amplifier Fl, switching logic compre-, hensive two gate circuits Gl, G2 for breaking information path between the connection device input and output transformer | is by receiving an inhibition signal from the terminal transmitting '30 logic, and an output amplifier F3 connected to the output transformer.

in

Three optocouplers 01, 02, 03, for example. manufactured by HEWLETT PACKARD 1, Type 6N 137 is connected between the connecting unit and 1 '35! terminal sending -and receiving logic that galvanic isolation. i.

, 1

The terminal T includes, one ADLC circuit of conventional type, · eg. \ \ MOTOROLA M6854, and loop logic which, under the control of a ij · _1 ί microprocessor CPU, for example. MOTOROLA type M68000, (not shown) comprising said transmitting and receiving logic A.

! 5 A omkoblingsforløp with the help of the device stated] IAA follows. i. ·, -i! 'j

Information fraringbussen RB applied to input a / b on trans- ji FORMATOR TRI in connection unit CU. When it enhetenj 10 - CU connected terminal does not force fed, passing the feed through the amplifier Fl, in which it is regenerated.!

The regenerated data stream passes gjennom.utgangsforsterkeren F3 and output transformer TR2 and once more out on the bus RB.

In this case, the connection unit only acted like a 15 amp.

In the. case where the terminal is force fed, but not yet!

# J In

connected to the bus, it seems connection unit anew as a for-i. amplifier, but the information is received simultaneously on the terminal received j 20 taksinngangen RxD via amplifier F2 and optocoupler 02 '. !

The terminal T then analyzes the information while awaiting j 'on the emergence of meddelselse in the form of a given code combination j. Clock to the entrance RxC at terminal j portion T sent simultaneously from connection device clock Cli j • 25 via optocoupler 01. · ..!;

; IN

In reception voltage logic A of the terminal section T made a roll-1 Equation between received code combinations and fixed combinations, and the compliance, i.e. when the terminal wishes 30 to send, transmit a blocking signal I to an input of each; of gate circuits Gl, G2, in the connecting unit . The inputs are,; inverting and the activation, for example. using logical 'l's, the path from the amplifier Fl and output amplifier F3. . The terminal TI sends the information via 35 a gate G3 and an amplifier F4 to the transmitter output TxD via: connection device transformer TR2 out of the ring bus RB.

1 this case controlled information through the terminal and connecting device shunt function is canceled. 1 what has been described it will be apparent that for an interrupt.

%. '.......] Ί

5 In

1 ί in the terminal, the lock signal does not arise and the device is operational once more as an amplifier, that is, no interruption in any terminal TI - T6 can give rise to an interruption in the bus.

5 The described electronical switching may of course be performed optically using optical fiberomkoblere, wherein the electronic switching logic then replaced by optical switches, for example. manufactured by NIPPON ELECTRIC, type OP-8751 ..

in 10 I. .

for 15 hours in · I!

IN

ii | 'In 25 I! ) In •:. '' | | 30. : III: 35 to 1! . · 'Ij

! IN

in ί in