455-607
AU 26S
2/4/86
XR
EX
41568e931
United States Patent [191
[11]
Patent Number:
4,568,931
Biolley et a1.
[45]
Date of Patent:
Feb. 4, 1986
[54]
4,399,563
DIGITAL INFORMATION TRANSMITTING
SYSTEM THROUGH AN OPTICAL
TRANSMISSION MEDIUM
Mozart, 75016 Paris; Jean M.
Boulaye, Rue De La Paix, 91360
Villemoisson-sur-Orge; Bernars F.
Maurel, 163 Rue De Charonne,
75011 Paris, all of France
[21]
[22]
[30]
Appl. No.: 443,686
Filed:
Harris .............. ..
.. 340/870 28
4/ 1984
Schussler .............................. .. 370/3
FOREIGN PATENT DOCUMENTS
2473823
7/1981
France .
Primary Examiner-Donald J. Yusko
Attorney, Agent, or Firm-Lowe, King, Price & Becker
[57]
ABSTRACT
The digital information transmitting system comprises
_
Nov. 22, 1982
Foreign Application Priority Data
Nov. 25, 1981 [FR]
Greenberg ........................ .. 455/612
4,417,334 11/1983 Gunderson et al.
4,441,180
[76] Inventors: Alain P. M. Biolley, 46 Avenue
8/1983
4,408,307 10/1983
France .............................. .. 81 22070
[51]
Int. Cl.‘ ........................ .. H04Q 9/00; HO4J 3/02;
[52]
US. Cl. ................................. .. 340/825.57; 370/4;
[58]
Field of Search .................... .. 340/825.57, 870.28;
H04B 9/00
455/607
350/9616; 370/1-4, 16, 56, 91; 455/603, 606,
612, 613
several subscriber stations and a processor for managing
the exchange of information between said stations. The
processor includes several optical circuits for receiving
information emitted from the optical emitters in the
stations respectively, and a single optical circuit for
emitting grouped informations to all the optical receiv
ers of the stations. An optical transmission pluribus is
interconnected between the stations and the processor.
The optical pluribus comprises several optical unidirec
tional forward lines for each linking the respective sta
References Cited
tion emitter to a respective receiving circuit of the pro
cessor, and a single optical unidirectional distributed
U.S. PATENT DOCUMENTS
backward line for linking the single emitting circuit of
[56]
4,288,869
9/1981
Kolodzey et a1. .................... .. 370/4
4,313,192
1/1982
Nelson et a1.
4,326,298
4/ 1982
. .....
. . . . ..
the processor to all the station receivers.
370/4
Fromm et a]. .................... .. 455/607
OPT/CAL L‘DUPLERS
13 Claims, 14 Drawing Figures
US. Patent
Q01
Feb. 4, 1986
Sheet 3 oflO
4,568,931
1
4,568,931
DIGITAL INFORMATION TRANSMITTING
SYSTEM THROUGH AN OPTICAL
TRANSMISSION MEDIUM
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to digital information or data
transmission along an optical bidirectional transmission
medium.
More particularly, the invention concerns a digital
information transmitting system that essentially com
prises several stations, each including an emitter and a
receiver, and information processing means for manag 15
ing the information emissions and receptions between
the stations. The processing means and the stations are
interconnected to the optical transmission medium such
2
the multiple subscriber lines connected to the bus and
on the system configuration.
OBJECTS OF THE INVENTION
The main object of this invention is to provide a
digital information transmitting system wherein time
division multiple access on a forward line, from the'
stations to the processing means, as in the prior art, is
not provided. Instead, multiple access in a processor
referred to as a concentrating and switching central
processor (CSCP) is generally performed on a back
ward line. A system of this nature is termed a optical
pluribus.
SUMMARY OF THE INVENTION
The optical transmitting system embodying the in
vention is such that an emitter in each station is con
nected to one receiver of the a processing means via one
that an emitter of a given station may communicate
individual optical line called an optical forward line. A
with the receivers of one or more given stations. The 20 receiver in each station is connected to an emitter of
optical transmission medium usually, called an optical
said processing means that is common to the stations via
bus includes one or more optical ?bers in a garland or
a distributed line between said stations, called an optical
star array connecting the emitters and receivers via the
backward line.
processing means. The information transmitted in-line
The emitter of said processing means transmits all
usually takes the form of a series of luminous pulses or 25 information signals along said backward line at a bit rate
bits resulting from a known coding operation, e.g. pulse
code modulation (PCM).
A message is formed of a series of bits directed from
an emitter of a given station toward one or more receiv
ers of other stations. Besides useful data, this message
can comprise service, synchronization and address in
formation along with any other information required
higher than that of the forward lines. The processing
means comprises means for receiving the information
signals emitted from the stations in an asynchronous or
synchronous fashion.
In accordance with an aspect of this invention, the
information processing means comprises means con
nected to the receiving means of the processing means
for recovering a clock signal derived from each of said
stations. Means connected to said clock signal recover
2. Description of the Prior Art
Optical bus transmission systems are already known. 35 ing means recognizes and detects headings of the mes
sages emitted by the station emitters. Means connected
French patent application 2,473,823 describes an optical
to said heading recognizing and detecting means stores
bus transmission system in which each emitter commu
the useful information emitted by said station emitters.
nicates with the other emitters through an optical trans
Means
connected to said storing means and controlled
mission medium called a bus. In response to each data
by said heading recognizing and detecting means
transmission, a processing means authorizes a station to
for the message transmission.
emit and authorizes at least one other station to receive;
to this end the processing means sends orders along the
bus, in accordance with a given exchange procedure.
The optical ?ber garland-arrayed systems cannot, as a
result of the optical link analysis, accept a high number
of shunt and insertion branches on a single optical line.
Those lines that carry repeater-regenerators introduce
phase shifts and additional noise, giving rise to a reduc
tion in the useful pass band of the line and a limit on the
maximum distance between remote subscriber stations.
The systems making use of star-array passive cou
plers introduce considerable attenuation in the optical
groups the stored useful information with a predeter
mined heading. The grouped information signals are
encoded and coupled to said emitting means of said
processing means.
In accordance with another aspect of this invention,
the optical transmitting system may comprise one or
several processing means and other optical forward
lines and other optical backward lines, either for reliev
ing a group of stations or for processing several groups
of stations that may communicate with each other.
The optical transmitting systems embodying the in
vention allows practically permanent self-control of
each transmitting line without the messages emitted
from a station being disturbed by the messages emitted
by the other stations. The optical transmission system as
signal. Such systems on special components that are
difficult to double up and which determine the optical 55
transmission characteristics.
per the invention makes it possible to overcome the
Furthermore, should a subscriber station become
vulnerability of traditional transmitting systems to ra
defective, the optical bus can be disturbed and ad
dioelectric or electromagnetic interference.
versely affect the transmission of other messages. Seek
The optical transmitting system embodying the in
ing out the failure or checking the circuits induces dis
vention makes it possible to side step the digital bit-rate
turbance of the same nature. Such systems provide
limitation drawbacks associated with traditional optical
periodic processing of the bus lines in order to attribute
buses. Moreover, when any number of stations is intro
an emission time to each station. Lastly, more recent
duced or dropped from the system within the maximum
systems include a programming mode covering message
limits envisioned, there need not be any adjustment of
transfer along the bus in order to provide bus access 65 the optical transmission or any modi?cation in the oper
possibilities at times chosen by the subscriber. How
ational software.
ever, the precise moment when the bus becomes avail
The optical pluribus embodying the invention does
able depends on the traf?c at the particular instant along
not call for an active repeater at each subscriber station
3
4,568,931
4
and affords a substantial transmission margin allowing
lamination period as long, whilst a bit 1 comprises an
the use of high attenuation optical lines.
illumination period equal in duration to t/2 followed by
an obscurity period as long. The invention may well be
applied in a similar fashion to other types of coding, for
instance, ?ve bits-six bits code or CMI code.
BRIEF DESCRIPTION OF THE DRAWING
Other objects, features and advantages of the inven
tion will be apparent from the following more particu
lar description of the preferred embodiments of the
invention as illustrated in the accompanying drawings,
in which:
FIG. 1 is a schematic block diagram of a system com
prising a central processor and a optical backward line;
FIG. 2 is a block diagram of the concentration and
switching central processor (CSCP) in FIG. 1;
FIG. 3 is a variant of FIG. 2;
FIG. 4 is a block diagram of a subscriber station of
Consequently, for example, the message emitted by
the emitter E,- of station S,-is transmitted via the forward
line 1, to the receiver R’, in the concentration and
switching central processor CSCP. In reference to
FIGS. 2 and 3, each receiver R'iincludes a photodetec
tor 10,-such as a phototransistor or a photodiode which
receives the light beam propagation on the respective
optical line 1,. The photodetector 10,-is connected across
FIG. 1;
the terminals of the input circuit of a current-voltage
preamplifier 11,-having an output for deriving a voltage
in terms of the current generated by the photodetector
FIG. 5 is a block diagram of a relieved system includ
ing the processor illustrated in FIG. 1 and a spare pro
10,‘.
The output preampli?er 11,- is connected to the input
of a clock and data recovering circuit 12,. Circuits such
FIG. 6 is a variant of FIG. 5 with two backward 20 as these are well known. Indeed, numerous circuits for
cessor;
lines;
clock recovery in an asynchronous and synchronous
mode information transmission have already been dis
backward lines;
closed. However, to permit clock recovery and to
FIG. 8 is a block diagram of a system comprising two
avoid using an additional line for transmitting the syn
interconnected groups each including stations and a 25 chronization signals, the code for emitted messages is
central processor;
selected as self-synchronizing. The aforementioned
FIG. 9 is a variant of FIG. 8 including two federate
codes satisfy this criterion.
pluribuses;
Once the clock signal has been recovered, the infor
FIG. 10 is a block diagram of system with hierarchi
mation is fed into the input of a heading recognizing and
30
zation of station groups;
detecting circuit 13,-. A heading is a status word accom
FIG. 11 is a variant of FIG. 1 with shared-emission
panying each message and preceding the useful data in
FIG. 7 is a variant of FIG. 1 with two distributed
forward lines;
FIG. 12 is a variant of FIG. 1 in which the optical
pluribus is relieved by means of speci?c redundancy;
FIG. 13 is a variant of FIG. 1 with redundancy in the
backward line; and
FIG. 14 is a variant of FIG. 1 with wavelength-divi
sion multiplexing.
DESCRIPTION OF THE PREFERRED
EMBODIMENTS
With reference to FIG. 1, n subscriber stations S1, S2,
S3, . . . S,,_1, S,, are each connected, according to the
invention, to a concentration and switching central
processor (CSCP) through an individual optical unidi
the message. This heading can constitute an urgency, a
priority level, an information indicating the message
type, the length of this message, the addressee, the ori
gin, etc. It can be formed of one or more words. The
headings leaving the n headings recognizing and detect
ing circuits 13; to 13,, are fed into n inputs 1501 to 150,,
of a control processor 15. This processor 15 applies
these headings either as is, or modified, or reconstituted
in terms of the application, to the input 160 of a heading
register 16. Indeed, the processor 15 can control frag
mentation of the message, repetition of said message, an
ancillary device should an error or another phenome
45 non be detected, and modify the information of this
heading. Message switching toward a heirarchized or
federate system can also be controlled by this processor
of an optical waveguide such as a single optical ?ber.
15 as will be made clearer hereinafter.
Each station S; with léién, essentially comprises an
The heading recovering and detecting circuits 131 to
optical information emitter E,- and an optical informa
tion receiver R,~. The it forward lines 11 to l,,, referred to 50 13,, deliver the useful information to the inputs 14-01 to
14-0,, of n registers 14] to 14,,. The processor 15 delivers
as optical subscriber lines, are respectively connected to
a reading clock signal H to the registers 14] to 14,, via
n individual optical information receivers R’; to R',,
wires 1411 to 141,, to control the extraction of data from
included in the central processor CSCP. The n receiv
rectional forward line l1, l2, l3, . . . l,,_1, l,, which consists
said registers. The reading clock signal in accordance
ers R1 to R,, in the subscriber stations S1 to 8,, are also
connected, in accordance with the invention, to a single 55 with the invention has a high frequency 20 to 40 MHz
or more for instance. A register 17 receives the data
common optical unidirectional backward line 1, via
derived from the registers 141 to 14,, and introduces a
connection ?bres f] to t‘, which are coupled up to the
heading ET which corresponds to the extracted data
message; heading ET is coupled to wire 161 from the
The central processor CSCP transmits the messages
along the backward line I, by means of a single informa 60 heading register 16 at the rythm of the signal H applied
from the processor 15 via a wire 162. The heading ET
tion emitter E’.
can be inserted either at the beginning of the message, in
The messages are transmitted in the lines in the form
the middle of a fragmented message, or at any predeter
of a light beam that is pulse code modulated (PCM). A
mined position. The register 17 serially transmits the
message is made up of a series of bits carrying binary
values 1 and O. The length of each bit is equal to the time 65 various messages derived from the n registers 141 to 14,,
to the output of the concentration and switching central
t. Several types of coding are possible. In the Manches
processor CSCP, via the input of a transcoding circuit
ter modulation, for instance, a bit 0 comprises an obscu
18.
rity period equal in duration to t/2 followed by an il
backward line I, by means of optical couplers C1 to C,,.
5
4,568,931
It will be observed that the n data registers 14] to 14,,
are ?rst-in, ?rst-out memories (FIFO) or any other
RAM memories capable of storing the incoming data
emitted by the respective subscriber stations. However,
these it RAM memories can be replaced by a RAM
memory 14 bis common to the n forward lines, as de
picted in FIG. 3. The circuit 18 receives the information
from the register 17 and transcodes these serialized data
so they are compatible with the emitter E’. Indeed, a
single emitter E’ in the concentrating and switching
central processor (CSCP) is sufficient. Emitter E’ essen
tially comprises a preampli?er 19 followed by a photo
emission element 20 such as a laser diode or an LED
diode which emits a light beam that is incident on the
6
their headings'Likewise, a transcoding circuit 18’ per
forms the desired coding at the output of the register
18'. The information signals are then emitted along
backward lines 1, and 1’, through the emitter E’ and an
emitter E". It will be noted that the second backward
line I’, may have a rate differing from that in the line 1,
depending on the number of addressee subscriber sta
tions served.
In the embodiment as depicted in FIG. 3, the RAM
memory 14 bis could, further, contain the headings in
which case the processor 15 would process these head
ings by writing or reading directly into this memory,
thereby doing away with the register 16.
FIG. 4 is a block diagram of an embodiment of a
entrance end of an optical ?ber forming the high bit-rate 15 subscriber station Si likely to emit messages toward a
backward line 1, to the receivers R1 to R,, of the sub
processor CSCP by means of its respective forward line
scriber stations 5] to S”.
I,- and receive the messages convoyed by the backward
Choosing the backward line bit rate of line 1, depends
line 1,. The receiver R; of station S,- is connected to the
primarily on the number of subscriber stations 5] to 8,,
backward line 1, by means of a connection ?ber f,-which
connected to the concentrating and switching central 20 is coupled to the line 1, via an optical coupler C1. The
processor CSDP and on the bit rate in each of these
receiver R,-chie?y comprises a photodetector such as a
photodiode or a phototransistor, that is connected
the simultaneous bit rates taken as a whole over these
across the terminals of a current~voltage preamplifier.
various equipment items may flow with a very comfort
The receiver Ridelivers electrical pulses in series to the
able useful occupation rate margin. In practice, a bit 25
input of a transcoding circuit 20. The circuit 20 essen
rate over the backward line of around 20 Mbit/s to 40
tially performs a decoding operation on the received
Mbit/s or more is adopted.
informations,
a series-to-parallel conversion of the re
It will be noted that the transcoding circuit 18 tran
equipment items. The backward line is chosen such that
ceived signal and a check of its parity. The signal de
scodes the data on the backward line I, in terms of a
code which generally is different from the code utilized 30 rived from the circuit 20 is applied to an input 300 of a
processing device 30. The device 30 essentially com
over the various forward lines 11 to l,,.
prises a message reception table and a message emission
The reception of information as described here for
table.
Based on the headings, the message reception
the n stations 5] to S" is asynchronous. Indeed, this
table recognizes, on the one hand, the messages emitted
arrangement provides the widest operational flexibility.
The system would, however, also be applicable to a 35 by the station 5;, and on the other hand, the messages
that are transmitted from other stations to the station 8;.
synchronous message transmission.
A comparator inserted in the device 30 veri?es, by
A further advantage of the system based on a back
straightforward comparison of the message received
ward line managed by the processor CSCP and distrib
against the emitted message contained in the emission
uted to the stations resides in recognizing the priority
table, the transmission quality for any message. The
reigning over the incoming message and in modifying
comparator can then validate the message and delete
the retransmission order thereof after modifying the
said message from the two tables.
message headings when necessary. The processor
Similarly, the processing device 30 includes a mes
CSCP exercises an urgency, priority, bit-rate compro
sage emission table where the information signals to be
mise for traffic flow.
A modi?cation regarding the headings may also be 45 emitted on the forward line I,- are stored and where the
eadings of the emitted information signals are prepared
advantageous in the event of data dating.
in accordance with the pluribus organization. The infor
The optical pluribus embodying the invention affords
mation signals derived from the emission table with
numerous advantages in transmitting messages between
completed headings are therefore fed into the input 400
subscriber stations. The time division multiple access is
carried out in the CSCP processor itself and along the 50 of a transcoding circuit 40 for encoding the message,
verifying the parity of said message and performing a
backward line; this is in contrast to the time division
parallel-to-series conversion. Then the message derived
multiple access that was performed by the optical bus in
from the circuit 40 undergoes an electrical-optical con
the prior art. Such a transmission mode protects against
scrambling, should a subscriber station incur a failure
version, provided by emitter E; that, for instance, in
and emit erroneous messages. Furthermore, it provides
self-control in each station through comparison of the
cludes a diode LED which transmits the light message
message emitted along the respective forward line
against that received by the backward line as will be
come clear from the subscriber station description.
FIG. 3 is a circuit diagram of a concentrating and
switching central processor CSCP which retransmits
the messages along two backward lines 1, and l’,. Let it
along the forward line 1;.
The processing device 30 as a result of its two emis
sion and reception tables makes it possible to receive
and emit the message in perfect asynchronism with a
subscriber equipment 50 of the station 8;.
Links, not illustrated, between the equipment 50 and
the processing device 30 permit information exchange
be supposed that for bit-rate, redundancy or other rea
sons, a second backward line I’, is necessary. With this
in mind, the processor 15 extracts from the memory 14
his in FIG. 3 information which is applied partly to the
management, information transfer interruption or any
error to be made known. The device 30 is responsible
input of the register 17 and partly to the input of a
register 17'; memory 14 bis furnishes messages with
sage not received by the processor CSCP, and advising
for managing the pluribus transmission, holding in
memory or repeating any erroneous message or mes
the processor CSCP that the station S,- is ready to re
7
4,568,931
8
ceive messages. To sum up, the device 30 monitors
message transmission.
E'b of processor CSCPI, to receiver R',,[, of processor
The device 30 may also be simpli?ed without chang
ing the message transmission mode of the invention.
Indeed, if the self-control regarding messages contained
in the emission and reception tables is not necessary, the
subscriber station results in being lightened. This is
subscriber stations S1 to S”. Dots will be adopted in
FIG. 6 and in the description hereinafter to represent
optical distributors and couplers. As a result, in FIG. 6,
each subscriber station A,- emits toward the respective
receivers R’b; and R',; of processors CSCPa and CSCPI,
by means of its emitter E,-.
CSCPb and to second receivers such as R1 to R,, of
generally the case when the emission tables are in the
If it is assumed that the processor CSCPa is active and
In the event of message multirouting, the device 30 0 the processor CSCPb is in relieving position, then the
subscriber equipment.
can further provide for grouped addresses or single
addresses. Such an embodiment is of particular interest
emitter E’a emits all the messages grouped together
along the high-rate backward line in, and distributes
when the pluribuses are hierarchized as will be ex-'
them to the subscriber stations. The receiver R'ba in
relieving processor CSCPb also receives the messages
from the line In, and compares these messages against
plained hereinafter.
The invention opens the way to many con?gurations
due to the absence of constraints on the backward line.
In reference to FIGS. 4 and 5, a particularly advanta
those received via its own receivers R’bl to R'bn con
nected directly along the pluribus forward lines. If it is
supposed that the grouped message emitted along the
geous embodiment of the invention makes it possible to
backward line In, is incorrect, then by means of a prede
relieve the transmission by doubling up the concentrat
ing and switching central processor CSCP. In this fash 20 termined procedure, the processor CSCPI, substitutes
for the processor CSCP‘, and emits through its own
ion, two processors CSCPa and CSCPb are located at
emitter E'b along the other backward line 1,1,.
separate well spaced-out positions. The messages deliv
ered by the emitter E of subscriber stations S are re
Reciprocally, the processor CSCP‘, then goes into a
ceived by receivers R'ai and R’[,; that are respectively
relieving position. The subscriber stations do, however,
included in the processors CSCP‘, and CSCPb and are of 25 'in this embodiment, include a second receiver-not
shown-for receiving the messages along the backward
the type described according to FIG. 2. An optical
distributor D,- splits the light beam that is emitted by
line lrb.
station S,-_. between forward lines that are connected to
The concentrating and switching central processors
the receivers R',,[ and R’bi of the processors CSCP‘, and
CSCP can thus be doubled or indeed tripled where
30 these redundant processors can be located at relatively
CSCPb.
remote positions thereby reducing the simultaneous risk
of physical interference in these items.
FIG. 5 however, depicts an embodiment including
just one distributed backward line 1,, on which the in
FIG. 7 is a block diagram of an optical pluribus ar
formation signals are emitted either by the emitter E',, of
rangement embodying the invention that comprises two
the processor CSCPa or emitter E’[, of the processor
CSCPb, only one of which is active. Indeed, the back 35 optical backward lines 1', and 1'', that are distributed for
subscriber stations S1 to S” and connected to a single
ward line 1, is common to the two processors CSCPa
processor CSCP. It may be supposed that two given
and CSCPb; it is connected for the direction from the
stations, e.g. S,,_1 and S” for urgency or priority rea
processor CSCP, to the processor CSCPb, to the emit
sons, must have wide accessibility in order to receive
ter E’, of processor CSCP” and an additional receiver
R’ba of processor CSCP’, via a coupler Cab, couplers C1
to C" and a coupler Cba, and it is connected for the other
direction from the processor CSCP], to the processor
CSCPa to the emitter E’b of processor CSCPI, and an
additional receiver R',,;, of processor CSCPb via cou
plers Cba, C” to C1 and Cab.
40
the information arriving from the other stations. The
second backward line 1",is provided for solely connect
ing these two subscriber stations 8,, and S,,_1 to an
additional individual emitter E" in the processor CSCP.
Contrary to the aforesaid, the (n-2) other stations are
45 connected to the emitter E’ in the same processor CSCP
that emits the distributed information along the back
ward line l',. Such a layout may also be necessary for
optical analysis purposes when the number of shunted
high rate; processor CSCPI, compares the high-rate
stations in a line is too high. Here again, the control
backward line message received by the receiver R'ba
with the messages received by its own receivers R'bl, 50 processor 15 of the processor CSCP is responsible for
managing the information signals emitted by emitters E’
R'bz, . . . R’bi, . . . R‘;,,,. If it is assumed that the message
and E" as mentioned in reference with FIG. 3.
emitted along the backward line by the processor
FIG. 8 relates to an embodiment of the invention
CSCP‘, is erroneous, then a predetermined procedure
wherein two pluribus networks Ba and Bb are intercon
makes it possible to inform the processor CSCPb along
the same backward line I, that it should take over. The 55 nected and each is formed of a respective number Pa,
P1, of subscriber stations and a respective individual
processor CSCP1, then emits messages distributed to the
central processor CSCPa, CSCPb. The processors
subscriber stations 8] to 8,, along the same backward
CSCP” and CSCPI, are not however independent. The
line I, through its emitter E’!,. On a reciprocal basis, the
?rst pluribus 13,, is connected for example to Pa=3 sta
processor CSCP” acts as safe circuit and receives, via its
receiver R'ab, the high-rate backward line message 60 tions Sal, Sag, $83 which emit information signals that
are transmitted by the individual forward lines 141, 1,1,
emitted by the processor CSCPb.
183 and received by means of receivers R'al, R’aZ and
FIG. 6 like FIG. 5 depicts a pluribus relieved by
R',,3 of the processor CSCP“. Coming the other way,
doubling up the processor CSCP but with independent
the emitter E4 of processor CSCP“ transmits the
backward lines In, and 1,1,.
The backward line lm links the emitter E'a of proces 65 grouped informations to the receivers R41, R41, R43 of
these three stations along the distributed backward line
sor CSCP‘, to the receiver R'ba of processor CSCPI, and
1",. The backward lines In, conveys, however, in accor
to ?rst receivers such as R] to R" of the subscriber
dance with this embodiment, information signals in
stations S1 to S”. The backward line 1,1, links the emitter
The processor CSCP}, thus in a relieving position
receives, like a subscriber station, the entire message at
4,568,931
»
9
tended for additional subscriber stations SM and SM of a
second pluribus B1,. The two subscriber stations Sbk and
SM are connected to pluribus B, by means of two ?rst
10
la and a respective common backward line 1N1, 1,1,, 1”,
1,11. Thus, receivers R'al, R'az and R'a3 in the processor
CSCPa receive informations emitted from respective
stations Sal, 8,3 and S03, and the emitter E'a of the pro
cessor CSCP‘, sends the information back along the
respective high-rate backward line I”, to stations Sal,
receivers in these two stations that are connected to the
backward line l,a via optical distributors (not shown),
and by means of two additional receivers R’ak and R'a1
in the processor CSCPa via two emitters in these two
stations and via two additional optical forward lines lak
Sn; and S83. Similarly, the other processors CSCPb,
CSCPC, CSCPd, communicates with their respective
subscriber stations via their individual forward lines and
and la].
The second pluribus B1, links, for example, the emit
their common backward line.
Assume that a certain number of information items
ters of P1,: 3 subscriber stations 51,1, 81,2, 5],; to receivers
R'bi, R'bz, R’/,3 in the processor CSCP;7 via forward lines
gathered by a station such as station Sag of the pluribus
B,,, has interested another station, such as station Sdz of
lb], 15;, 11,3. The subscriber stations Sb], S112, S1,; receivers
respond to the information signals propagating in the
another pluribus Bd.
backward direction on single distributed backward line
lrb as emitted from the emitter E'b in the processor
CSCPb. Each of stations Sbk and Sm includes a second
receiver R connected to the distributed backward line
1,1,. The single emitters E in each of stations Sbk and S1,]
In FIG. 10, there is no direct transmission from one
pluribus to the other; instead there is a transmission via
a so-called higher order pluribus Be. Such an arrange
ment is termed hierarchization. All the information
signals from one low order pluribus B,,, B1,, B6, Ed in—
are also connected to respective additional receivers 20 tended for another low order pluribus are oriented and
transmitted to the high order pluribus Be which returns
R’;,;,-, R'[,] in the processor CSCPb via respective addi
them to the other low order pluribuses along another
tional optical forward lines lbk, 11,1. Emitter E is in
common high rate backward line.
tended to emit as well to the processor CSCPa via the
respective line lak, 101 as to the processus CSCPb via the
The pluribus Be includes four forward lines In, lbe, lee,
respective line lbk, 11,].
25
FIG. 9 concerns a particular embodiment of two
the processors CSCPa, CSCPb, CSCPC, CSCPd to re
ceivers Rea, Reb, Rec, Red in the processor CSCPe, and a
called federate pluribus networks Ba, B1,. If the ?rst
pluribus 13,, comprises n subscriber stations $01 to S4,,
common distributed backline line 1,8 that links an emitter
E8 in the processor CSCPe to receivers R'ae, R'be, R’ce,
R'de in the processors CSCPE, CSCPb, CSCPC, CSPDd.
Looking again at the above example of the station 502 in
the pluribus Ba and the station Sdz in the pluribus 8,1
which wish to exchange information signals, the emitter
E’ae of the processor CSCPa communicates with the
that are connected to a processor CSCPa by means of n
forward lines la] to la” and one distributed backward line
1m and if the second pluribus B1, comprises 111 subscriber
stations Sbi to S1,”, that are connected to a processor
CSCPb by means of in forward lines 11,1 to 1b,, and one
distributed backward line 1,1,, then the two pluribuses
are termed federate if they intercommunicate via their
receiver Rea of the high order central processor CSCPe.
Likewise, each pluribus B1,, Bc, Bd communicates with
the high other pluribus Be by means of the respective
emitters E'be, E’“, E'de and the respective receivers Reb,
backward line. Indeed, FIG. 8 related to a communica
tion between two pluribuses via at least an additional
forward line ascribed to a subscriber station desirous of
communicating with the other pluribus.
According to the embodiment of FIG. 9, the back
lde that link respectively emitters E'ae, E'be, E'ce, E'de in
Rec, Red for all the messages sent from its respective
40 stations and not intended for these stations. Each low
ward line in each of the two pluribuses B,,, B1, is also
distributed to the other pluribus B;,, B,,. The information
order processor CSCPa, CSCPb, CSCPC, CSCPd acts as
a subscriber station for the high order pluribus Be. The
signals on the backward line 1”, are received in an addi
tional receiver R’ba in the processor CSCPb via a con
“outside” emitting line I“, lbe, lee, 1.18 of pluribuses B,,,
B1,, Bt, Bd may also be a high rate optical line.
nection forward line 11,4, whilst the information signals 45
The high order processor CSCPe, also arranged as
on the backward line 1,], are received in an additional
described in reference with FIGS. 2 and 3, delivers the
receiver R',,[, in the processor CSCPa via a connection
forward line lab. Each processor CSCPa, CSCPb re
ceives the message from the other pluribus Bb, Ba as if it
information at the output of its emitter E’e along the
high-rate backward line 1,8 to all the low order pluri
buses. Each pluribus B,,, B1,, BC, Bd receives via the
were a typical subscriber station and re-emits the mes 50
respective receiver R'ae, R'be, R'ce, R’de the information
signals supplied to it by the pluribus Be, recognizes the
signals intended for it through the headings of the infor
sages after discrimination along its own backward lines
1m, 1,1,. The particular stations 5,11 to San, SM to S1,"I
concerned with the message from the other pluribus B1,,
mation signals and retransmits a signal to its respective
Bd recognizes the heading and receives the message
backward line 1m, lrb, lrc, 1rd the information signals
55 intended for its subscriber station.
ascribed to it.
FIG. 10 is a block diagram of a further embodiment
In the embodiment shown in FIG. 10, the high order
of the invention in which there is a hierarchy of pluribus
networks. In fact, the pluribuses B,,, B1,, B6, B4 cannot
intercommunicate directly via the stations connected to
pluribus is connected only to low order pluribuses. It
would, however, further be possible for simple sub
scriber stations to be directly connected to the high
them as in FIG. 8 nor via the concentrating and switch 60 order pluribus 3,.
ing central processors CSCPa, CSCP1,, CSCPC, CSCPd
FIG. 11 is a block diagram of an optical pluribus
as in FIG. 9 but rather via an additional pluribus Be and
embodiment with a shared emission line. As in FIG. 1,
the n subscriber stations S1 to S,, are connected to a
' an additional processor CSCPe. In FIG. 10 are provided
four pluribuses Ba, Bb, BC and Ed, each of which bidirec
tionally links respective subscriber stations Sal, Sq, Sa3;
81,1, 51,2, 51,3; SE1, S,_-2; S41, Sun to a respective processor
CSCPa, CSCPb, CSCPC, CSCPd through respective
individual forward lines 141, la, 143; 11,1, 1172153; 1C] 162; 1d],
connecting and switching central processor CSCP by
65 means of individual forward lines 11 to 1,, and a common
backward line 1,. Certain stations can, however, be
made up of a group of several subscriber substations. In
this spirit, the station S3 is constituted by a group of
11
4,568,931
12
itself and to receive information signalsfrom every
other station and itself through said managing
three subscriber substations S31, S32 and S33 and the
station S,,.] is constituted by a group of four subscriber
substations S(,,_|)1, Sol-1);, S(,,_1)3 and S(n_1)4. Each
means,
each station including an optical information signal
emitter and an optical information signal receiver,
subscriber substation has an emitter and a receiver. The
information signals delivered from the substations in a
station such as station S3, S,,_1 are emitted in turn in
terms of how one and the same ?ber l3, l,,_1 is occupied
and received by the same receiver R'3, R',,_1 in the
processor CSCP. An internal protocol can facilitate the
said managing means including: plural optical signal
receiving means for converting said optical infor
mation signals derived by said station emitters into
corresponding electric information signals for the
optical information signal emitted by each of said
stations, means for processing said electric station
emission duration and the emission period of each sub
-' scriber substation included in the same station. These
subscriber substations in a same station are advanta
information signals to form a combined electric
geously chosen close to each other.
information signal, and a single optical emitting
means for converting said combined electric infor
FIG. 12 is an illustration of an embodiment with
speci?c redundancy. As illustrated in FIG. 1, n stations
mation signal into a combined optical information
5] to S,, are connected to the same processor CSCP by
means of an optical pluribus formed of n forward lines
ers,
signal to be distributed to all of said station receiv
11 to l,I and a single distributed backward line 1,. In FIG.
12, the station S,,_| receives information from the sta
tion S3 that is directly connected to the station S,,_1 20
without going via the optical pluribus-by means of a
simple optical ?ber, an optical distributor at the output
of the emitter of station S3 and a second receiver in
cluded in station S,,_ 1. This redundancy can be particu
said optical transmission medium comprising: plural
larly interesting when it relieves a priviledged transmis 25
ters, and a single unidirectional optical backward
line for carrying and distributing said optical com
bined information signal from said emitting means
in said managing means to all of said station receiv
sion from station S3 to station S,,_1.
FIG. 13 is a block diagram of a system analogous to
that in FIG. 1, but includes a pluribus carrying a multi
tude of high rate backward lines 1,1 to l", which are
connected to emitters E’; to E’, in the processor CSCP
respectively. Thus, if n subscriber station are connected
to the processor CSCP, they may be envisioned as n
individual backward lines on which the message are
again a superposition of the messages emitted by all the
stations. Such an arrangement endows redundancy on
unidirectional optical forward lines, each of said
forward lines being connected to unidirectionally
carry one of said optical information signals from
one of said station emitters to one of said receiving
means in said managing means, a different forward
line being provided for each of said station emit
ers.
2. The system according to claim 1 wherein said
combined information signals in said backward line has
a higher rate than the information rate of the signal in
each of said forward lines.
3. The system according to claim 1 wherein said
35 information signals derived from said station emitters
the pluribus backward line.
are in a synchronous mode.
The embodiment shown in FIG. 14 is a variant of the
embodiment shown in FIG. 1. Indeed, each subscriber
4. The system according to claim 1 wherein said
information signals emitted from said station emitters
are in an asynchronous mode.
5. The system according to claim 1 wherein the infor
means of an individual forward line 11 to 14 which is also 4-0
mation signal emitted from said emitter in each of said
intended as backward line for the subscriber station.
stations includes a heading and useful data information,
Indeed, the messages are multiplexed in wavelength
and wherein said processing means comprises: means
along one and the same optical ?ber, a wavelength M is
connected to said receiving means for recovering clock
chosen for the emission from a station to the processor
CSCP and a wavelength A; is chosen for the reception 45 signals relative to said stations respectively, means con
nected to said clock signal recovering means for recogé
from the processor CSCP to a station. Pairs of optical
station S1 to S" is connected to the processor CSCP by
separating ?lters F1 to F" are provided at the ends of the
nizing and detecting said headings in said message emit
bidirectional lines 11 to 1,, for achieving wavelength
ted from said station emitters, means connected to said
separation so that emitters of the stations and the receiv
ers R’; to R’,, of the processor CSCP operates at the
wavelength M and so that the emitter E’ of the proces
sor CSCP and the receivers of the stations operate at the
heading recognizing and detecting means for storing
other wavelength A2.
Further arrangements-not shown-of the pluribus
said useful data information in said messages emitted
from said station emitters, means connected to said
storing means and controlled by said heading recogniz
ing and detecting means for grouping the stored useful
information signals in each message with a predeter
stemming from various combinations of invention em 55 mined heading, and means for encoding the grouped
information signals into said electrical combined infor
bodiments may be made within the scope of the ap
pended claims.
mation signal so it is emitted by said single emitting
The invention could apply in particular to distributed
data processing and bureautics.
means.
What we claim is:
1. A digital distributed information signal transmit
ting system comprising:
plural stations,
6. The system according to claim 1 wherein each of
said stations includes: means for recognizing an optical
information signal on the backward line directed to it,
and means for coupling the recognized signal to the
signal receiver to the exclusion of the remaining signals
an optical transmission medium,
on the backward line.v
means interconnected to said stations via said medium 65
for managing information signal exchanges be
7. The system according to claim 6 wherein each of
said optical information signals includes a heading seg
tween ‘said stations, each station being fit to trans
ment and a useful information data segment, the head
mit information signals to every other station and
ing segment including an indication of the station to
4,568,93 l
13
14
receive the optical information signal, each of said sta10. A digital information transmitting system com
tions including means for transducing the optical inforprising:
mation signal on the backward line into an electric
?rst and second groups of stations, each station in
signal that represents the heading segment and the use
eluding an optical information signal emitter and an
ful information data segment, the recognizing means 5
optical information signal receiver,
including means for comparing the heading segment
an additional station includingan optical information
electric signal with a stored indication of the particular
signal emitter and ?rst and second optical informa
station.
-
8. A digital information signal transmitting system
comprising:
10
plural stations each including an optical information
signal emitter and an optical information signal
receiver,
?rst and second means for managing information
tion signal receivers,
?rst and second means respectively assigned to said
?rst and second station groups, each of said ?rst
and second means managing exchanges of informa
tion signals between said stations of said respective
group and the other managing means, each of said
managing means including several optical means
signal exchanges between said stations, each of said 15
for receiving information signals emitted from said
managing means including several optical means
emitters of said stations of said respective group
for receiving information signals emitted by said
respectively, a single optical means for emitting
emitters of said stations respectively, a single opti-
information signals to said receivers of said stations
cal means for emitting information signals to be
supplied to all of said receivers of said stations, and 20
of said respective group and to one of said ?rst and
second receivers of said additional station, and an
optical means for receiving information signals
emitted from said single emitting means of the
other managing means, and
additional optical means for receiving information
signals emitted from said emitter of said additional
station, and
an optical transmission medium connected between
said stations and said ?rst and second managing 25
means, said medium comprising plural optical unidirectional forward lines, each of said forward lines
linking said emitter of a respective station to a
?rst and second optical transmission mediums respec
tively assigned to said ?rst and second station
groups, each transmission medium being intercon
nected between said stations and said managing
means of said respective group and said additional
respective receiving means of one of said managing
station and comprising several optical unidirec
means and to a respective receiving means of the 30
other managing means through an optical distribut-
tional forward lines, each of said several unidirec
tional forward lines linking said emitter of a respec
ing means, and a single optical bidirectional distributed backward line for linking said single emitting
means of said ?rst and second managing means to
said receivers of said stations and said additional 35
receiving means of said ?rst and second managing
tive station of said respective group to a respective
receiving means of said managing means of said
respective group, a single optical unidirectional
distributed backward line for linking said single
emitting means of said managing means of said
means.
respective group to said receivers of all said sta
9. A digital information transmitting system comprising:
tions of said respective group and to one of said
two emitters of said additional station, and an addi
plural stations, each including an optical information 40
signal emitter and ?rst and second optical informa
tional optical unidirectional forward line for link
ing said emitter of said additional station to said
tion signal receivers,
additional receiving means of said managing means
?rst and second means for managing exchanges of
of said respective group.
information signals between said stations, each of
11. A digital information transmitting system com
said managing means including several optical 45 prising:
means for receiving information signals emitted
?rst and second groups of stations, each station in
from said emitters of said stations respectively, a
eluding an optical information signal emitter and an
single optical means for emitting information sig
nals to one of said ?rst and second receivers of all
said stations and to an additional optical means for 50
receiving an information signal emitted from said
single emitting means of the other managing means,
and
an optical transmission medium between said stations
and said ?rst and second managing means, said 55
transmission medium comprising plural optical
unidirectional forward lines, each of said lines linking said emitter of a respective station to a respective receiving means of one of said managing
means and to a respective receiving means of the 60
optical information signal receiver,
?rst and second means respectively assigned to said
?rst and second station groups, each of said ?rst
and second means exchanging information signals
between said stations of said respective group and
the other managing means, each of said managing
means including optical means for receiving infor
mation signals emitted from said emitters of all said
stations of said respective group respectively, a
single optical means for deriving information sig
nals supplied to said receivers of said stations of
said respective group and to the managing means
of the other group, and an additional optical means
other managing means through an optical distribut-
for receiving information signals derived by said
ing means, and ?rst and second optical unidirectional distributed backward lines, each of said
backward lines linking said single emitting means
single driving means of said managing means of
said other group, and
?rst and second optical transmission mediums respec
of one of said ?rst and second managing means to 65
one of said ?rst and second receivers of said sta
tions and said additional receiving means of said
other managing means.
tively assigned to said station groups, each trans
mission medium being interconnected between said
stations and said managing means of said respective
group and comprising several optical unidirec
15
4,568,931
16
tional forward lines, each of said unidirectional
forward lines linking said emitter of a respective
station of said respective group to a respective
receiving means of said managing means of said
respective group, and a single optical bidirectional
groups to said receiving means of said additional
managing means respectively, and a single addi
distributed backward line linking said single emit
ceiving means of said managing means of said
groups.
tional optical unidirectional distributed backward
line for linking said single emitting means of said
additional managing means to said additional re
ting means of said managing means of said respec
tive group to said receivers of said stations of said
respective group and to said additional receiving
means of said managing means of the other group. 10
12. A digital information transmitting system comprising:
13. A digital distributed information transmitting
system comprising plural stations,
an optical transmission medium,
?rst and second optical ?ltering means,
means interconnected to said stations via the trans
several groups of stations, each of said stations including an optical information signal emitter and an
optical information signal receiver,
15
several station information managing means respectively assigned to said several station groups, each
managing means including: several optical means
mission medium and said ?lters for managing infor
mation signal exchanges between said stations,
each station being ?t to transmit an information
signal to every other station and to itself and to
receive information signals from every other sta
tion and itself through said managing means,
for receiving information signals emitted from said
emitters of said stations of the respective group 20
respectively, a single optical means for deriving
information signals supplied to said receivers of
each station including an optical information signal
emitter operating at a ?rst wavelength and an opti
said stations of said respective group, and addi
tional information receiving and emitting means,
several optical transmission mediums respectively 25
assigned to said station groups, each transmission
medium being interconnected to said stations and
said managing means of the respective group and
cal information signal receiver operating at a sec
ond wavelength,
said managing means including plural optical receiv
ing means operating at said ?rst wavelength for
converting said optical information signals emitted
from said station emitters into electric information
signals respectively, means for processing said elec
tric station information signals to form a combined
comprising several optical unidirectional forward
electric information signal, and a single optical
lines, each of said forward lines linking said emitter 3O
of a respective station of said respective group to a
respective receiving means of said managing means
emitting means operating at said second wave
of said respective group, and a single optical unidi
rectional distributed backward line, said single
backward line linking said single emitting means of
35
length for converting said electrical combined in
formation signal into an optical combined informa
tion signal to be distributed to all said station re
ceivers;
said optical transmission medium comprising plural
said receivers of said stations of said respective
optical lines, each optical line unidirectionally car
rying said optical information at said ?rst wave
group,
additional means for managing information signals
length from said emitter of one of said stations to
one of said receiving means in said managing means
said managing means of said respective group to
respectively, and unidirectionally carrying said
exchanged between said station groups, said addi
tional managing means including several optical
means for respectively receiving information sig
nals emitted by said additional emitting means of
length from said emitting means in said managing
said managing means of said groups, and a single
said ?rst optical ?ltering means comprising plural
?rst optical ?lters, each ?rst ?lter coupling said
optical combined information at said second wave
means to said receiver of said station,
optical means for supplying grouped information 45
signals to said additional receiving means of said
managing means of said groups, and
an additional optical transmission medium interconnected between said managing means of said
groups and comprising several additional optical 50
unidirectional forward lines, each of said‘ several
additional forward lines linking said additional
emitting means of said managing means of said
emitter and receiver in one respective station to a
?rst end of one respective optical line, and
said second optical ?ltering means comprising plural
second optical ?lters, each second ?lter coupling
one respective receiving means and said single
emitting means to a second end of one respective
optical line.
"
S5
60
65
*
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