Note: Descriptions are shown in the official language in which they were submitted.
FJ-7048
-1- 133~418
SYSTEM FOR MONITORING STATUS
OF PLURALITY OF REPEATERS
BACKGROUND OF THE INYENTION
(1) Field of the Invention
The present invention relates to a system for
monitoring the status of a plurality of repeaters
located along transmission lines connecting terminal
stations in a communication system.
(2) Description of the Related Art
Generally, in a communication system, wherein
terminal stations are connected by transmission lines
for data transmission, repeaters are located along the
data transmission lines, and data is transmitted
through the transmission lines by using the repeaters.
Each repeater in the communication system as
mentioned above, usually is provided with the function
of detecting and indicating the status of the operation
2~ and an alarm status of the repeater itself, e.g., an
alarm st-atus showing a power failure, a removable unit
has been removed, or a break in an input line
(hereinafter all of the above statuses are called as the
repeater status).
Further, the current status of the repeaters
located along a transmission line must be known to the
terminal stations carrying out data transmissions
through the transmission line by using the repeaters, i.
e., the terminal stations must monitor the status of
each repeater.
Eigure 1 shows a typical arrangement of a two-way
digital data transmission system constructed between two
terminal stations.
ln Eig. 1, reference numerals 51 and 55 denote two
terminal stations connected by transmission lines 56,
57, whereby a data transmission can be made in both
directions. Reference numerals 52, 53, and 54 each
1338448
--2--
respectively denote a two-way repeater, located along
the transmission lines 56 and 57.
In a conventional method for monitoring the status
of a plurality of repeaters located along the
transmission lines connecting two terminal stations,
one or each of the terminal stations 51 and 55 sends a
polling signal (status request signal) to determine the
status of each of the repeaters, receives an answer to
the polling signal from each repeater individually, and
thus collect the current status information from all of
the repeaters.
The timing of the monitoring operation when the
abovementioned conventional method for monitoring the
status of repeaters is applied to the construction of
Pig. 1, is shown in Figure 2, and can be compared with
the timing when the method of the present invention,
which will be explained later.
In Fig. 2, the horizontal plane corresponds to a
geometrical extension from the terminal station 51 to
the terminal station 55 along the transmission lines 56
and 57 in Fig. 1, and the vertical plane corresponds to
a direction of the progress of time, wherein the arrows
a, a' , b, b' , c, and c' indicated by a thinner line
each shows a signal (or data) transmitted by the
abovementioned conventional method for monitoring a
status of repeaters, where a, b, and c correspond to
the aforementioned polling signals (status request
signals) sent to the repeaters 52, 53, and 54, and a' .
b' , and c' correspond to the aforementioned answers
to the polling signals from the repeaters 52. 53. and
54, respectively.
The timing of the monitoring operation when the
abovementioned conventional method for monitoring the
status of repeaters is applied to the construction of
Fig. 1, is shown in Figures 2 and 3. Fig. 2 shows the
timing when a break has not occurred in the transmission
lines, and Fig. 3 shows the timing when a break has
133~448
- -3-
occurred in a line in the construction of Fig. 1, for
example, between the repeaters 52 and 53 on the
transmission line 56. In Figs. 2 and 3, the timing of
the monitoring operation by the present invention is
5 also shown. Thus is explained later as a comparison with
the conventional method described herein.
When a break does not occur in the transmission
lines in the construction of Fig. 1, the operation of
polling and receiving the answer to the polling by the
terminal station 51 i s repeated for each of the
repeaters 52, 53, and 54, and thus the terminal station
can obtain the current status of all of the repeaters
in the time "X", as shown in Fig. 2.
In the abovementioned conventional method for
15 monitoring a status of repeaters, however, it takes a
long time to collect the current status information from
a plurality of repeaters located along a transmission
line because the polling operation must be carried out
at all of the repeate~s on a one by one basis, as shown
in Fig. 2.
In the abovementioned conventional method for
monitoring a status of repeaters, if a break in a
transmission line occurs in the construction of Fig. 1,
for example, between the repeaters 52 and 53 on the
25 transmission line 56, as shown in Figure 3, the terminal
station 51 receives the answer a' from the repeater 52
corresponding to the polling signal a from the terminal
station 51, but does not receive the answers b' or c'
from the repeaters 53 and 54, due to the line break.
Therefore, throughout these operations, the terminal
station 51 iudges that a malfunction has occurred
between the repeaters 52 and 53.
However, in the above conventional method, when a
break has occurred in a transmission line, great
inconvenience is caused because of the long time needed
to determine whether or not a break has occurred
between the terminal stations, and where the break has
1338448
_ --4--
occurred.
-
SUMMARY OF THE INVENTION
The object of the present invention is to provide
a system for monitoring the status of a plurality ofrepeaters located along a transmission line, wherein a
time needed to collect the current status information
from a plurality of repeaters is reduced, and in
particular, the occurence of a malfunction can be
quickly determined at a terminal station.
Therefore, according to the present invention,
there is provided a system for monitoring a status of a
plurality of repeaters wherein: at least one of the
terminal stations comprises a multiframe generating
means which generates data in a form of a multiframe
consisting of a group of consecutive frames, an address
of each of the repeaters being included in the
corresponding one of the consecutive frames; and each
of the repeaters comprises an address detecting means
which detects the own address of the repeater in one
frame among the consecutive frames, to determine a
receipt of the corresponding frame among the
consecutive frames, and an information adding means
which writes the current status of the repeater in the
frame which includes the own address of the repeater,
when the repeater receives that corresponding
consecutive frame.
133844~
_
BRIEF DESCRIPTION OP THE DRAWINGS
In the drawings:
Figure 1 shows a typical arrangement of a
two-way digital data transmission system constructed
between two terminal stations;
Figure 2 shows a timing of collecting the
current status information by the method for monitoring
the status of a plurality of repeaters according to the
fourth to seventh embodiments of the present invention
when a break has not occurred in the construction of Fig.
1, compared with the timing in the conventional method;
Figure 3 shows a timing of collecting the
current status information by the method for monitoring
the status of a plurality of repeaters according to the
fourth to seventh embodiments of the present invention
when a break has occurred in the construction of Fig. 1,
compared with the timin~ in the conventional method;
Figure 4 shows a typical arrangement of a
one-way digital data transmission system constructed
between two terminal stations;
Figure 5 shows a basic construction of the
first embodiment of the present invention;
Figure 6 shows a timing of collecting the
current status information by the method for monitoring
the status of a plurality of repeaters according to the
first embodiment of the present invention when applied
to the construction of Fig. 4, compared with the timing
in the conventional method;
Figure 7 shows a basic construction of the
second embodiment of the present invention;
Figure ~ shows a timing of collecting the
current status information by the method for monitoring
the status of a plurality of repeaters according to the
second embodiment of the present invention when applied
to the construction of Fig. 4, compared with the timing
in the conventional method;
Figure 9 shows a basic construction of the
1338448
-6-
fourth embodiment of the present invention;
Figure 10 shows a basic construction of the
fifth embodiment of the present invention;
Figure 11 shows the timing when the fifth
embodiment of the present invention is applied to the
construction of Fig. 4, and wherein a break occurs in
both the transmission lines 56 and 57, for example,
between the repeaters 52 and 53, compared with the
conventional method;
Figures 12 and 13 show examples of the
formats of the multiframe in the present invention;
Figure 14 shows an example of the format of
the service bits region in the format of Fig. 12:
Figure 15 shows the construction of the
repeater in an embodiment of the present invention:
Figure 16 shows the construction of the alarm
status information collecting portion in an embodiment
of the present invention: and
Figure 17 shows the construction of the
information adding portion in an embodiment of the
present invention.
1338448
--7--
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The first embodiment of the present invention is a
system of monitoring a status of a plurality of
repeaters located along a transmission line connecting
two terminal stations, and is applied to a system having
two terminal stations connected to each other by a one-
way transmission line, and a plurality of repeaters
located along the transmission line.
Figure 4 shows a typical arrangement of a one-way
digital data transmission system constructed between two
terminal stations, to which the first embodiment of the
present invention is applied.
ln Fig. 4, reference numerals 51' and 55' denote
two terminal stations connected by a one-way
transmission lines 56' , whereby a data transmission
can be made in one direction from the terminal station
51' to 55' . Reference numerals 52' , 53' , and 54'
each respectively denote a one-way repeater, located
along the transmission line 56' .
Figure 5 shows a basic construction of the first
embodiment of the present invention.
In Fig. 5, reference numerals 1 and 4 denote
terminal stations, 3 denotes a repeater (note only one
repeater 3 is shown as representative thereof in Fig. 5),
5 denotes a multiframe generating means, 6 denotes an
address detecting means, 7 denotes an information adding
means, 8 denotes a repeater means, and 9 denotes a
multiframe data receiving means.
In the construction of Fig. 5, a data is generated
in the terminal station 1 and transmitted through the
transmission line 2 to the other terminal station 4, by
the repeaters 3. The repeater means 8 shown in the
repeater 3 functions as a usual one-way repeater,
including amplifying, shaping, and retiming, etc.
A first characteristic of the first embodiment of
the present invention is that data transmitted from the
terminal station 1 to the other terminal station 4 has
1~38448
the form of multiframe consisting of a group of
consecutive frames, wherein an address of each of the
repeaters is included in the corresponding one of the
consecutive frames. The multiframe generating means 5
arranged in one of the terminal stations 1, generates
multiframe data as above, and the multiframe data
transmitted is received in the terminal station 4. The
multiframe data receiving means 9 in the terminal
station 4 is such that the terminal station 4 functions
to receive the multiframe data in the same way as a
usual terminal station in a conventional communication
system wherein multiframe data is transmitted.
A second characteristic of the first embodiment of
the present invention is that each of the repeaters 4
is provided with an address detecting means 6 and an
information adding means 7.
The address detecting means 6 in each repeater,
detects an own address of the repeater, in one frame
among the consecutive frames received at the repeater,
to recognize a receipt of the frame corresponding to the
repeater, among the consecutive frames, and the
information adding means 7 in each repeater, writes the
current status of the repeater, in the frame which
includes the own address of the repeater, when the
repeater receives the frame corresponding to the
repeater, among the consecutive frames.
According to the first embodiment of the present
invention mentioned above, first data in the form of a
multiframe consisting of a group of consecutive frames,
wherein an address of each of the repeaters is included
in the corresponding one of the consecutive frames, is
generated in the multiframe generating means 5 in at
least one of the terminal stations 1, and sent out on
the transmission line 2. Next, when the multiframe from
the terminal station 1 whi ch has sent out the multiframe,
reaches the first repeater (the repeater adjacent to the
terminal station 1). the address detecting means 6 in
1338~4~
g
the first repeater detects the address of the first
repeater in one of the consecutive frames of the
multiframe, and the information adding means 6 writes
the current status of the first repeater in the frame in
which the address of the first repeater is detected,
and then the multiframe is again sent out on the
transmission line 2.
When the multiframe from the above terminal
station 1 reaches the second repeater (the repeater next
in line to the above first repeater), the current
status of the second repeater is written in the frame
in which the address of the second repeater is detected,
and then the multiframe is again sent out on the
transmission line 2, by a the process simila`r to the
process in the first repeater, as mentioned before.
A similar process is carried out in each of the
following repeaters until, finally, the other terminal
- station 4 receives the multiframe data including the
status of all of the repeaters located along the
transmission line 2 between the two terminal stations 1
and 4, i.e., by sending multiframe data from one of the
two terminal stations to the other, the other terminal
station can collect the current status of all of the
repeaters located along the transmission line 2 between
the two terminal stations 1 and 4.
hn example of the timing of the operation of the
above first embodiment of the present invention is
shown in Fig. 6. Figure 6 shows the timing of
transmission of the status of the repeaters in the
construction of Pig. 4, where two terminal stations 51
' and 55' are connected by a one-way transmission line
56' and one-way repeaters 52' , 53' and 54' are
located along the transmission line 56' which
corresponds to the arrangement including only one way of
the two ways of data transmission in the arrangement of
Fig. l.
In Pig. 6, an arrow ~, indicated by a thick line
1338448
--10--
shows a path of multiframe data generated at and sent
out from the terminal station 51' ; an arrow ~z
indicated by a thick line shows a path of multiframe
data including data generated at the terminal station
51' , and the current status of the repeater 52'; an
arrow ~ 3 indicated by a thick line shows a path of
multiframe data including data generated at the terminal
station 51', and the current status of the repeaters
52' and 53' ; and an arrow ~ 4 indicated by a thick
line shows a path of multiframe data including data
generated at the terminal station 51 ' and the current
status of the repeaters 52', 53', and 54' . Therefore,
as shown in Fig. 6, the terminal station 51 receives
the current status of all repeaters 52', 53', and 54'
15 in a time Y, which is shorter than the time X needed in
the polling method in the prior art.
When a break occurs in a transmission line through
which a multiframe data is to be transmitted, for
example, a break has occurred between the repeaters 52
' and 53' in a transmission line 56' in a direction
from the terminal station 51 ' to 55 ' as shown in Fig.
4, multiframe data ~I generated at and sent out from
the termina] station 51' can not be transmitted beyond
the point of the break, and therefore, the terminal
25 s tation 55 ' can not receive data.
Namely, in a construction wherein two terminal
stations are connected by a one-way transmission line
and one-way repeaters are located along the
transmission line as shown in Fig. 4, when a break in
the transmission line occurs between the repeaters, no
information about this malfunction between the terminal
stations can be obtained at the terminal stations except
for the fact that a malfunction which prevents data
transmission between the terminal stations has occurred.
by the first embodiment of the present invention.
To solve the above problem, in a second embodiment
of the present invention as shown in Figure 7, each of
1~3-8~8
the repeaters 10 located along the transmission line has
additional means, an input line break detecting means
11 which detects a break in an input line, and a
multiframe generating means 12 having a basically the
5 same function as the multiframe generating means 5 in
the terminal station 1 except that the multiframe
generating means 12 in each of the repeaters operates
only when the break in an input line is detected by the
repeater.
The operation and timing in the second embodiment
of the present invention mentioned above, is explained
with reference to the timing chart of Fig. 8. Figure 8
shows the timing when the second embodiment of the
present invention is applied to the construction of Fig.
15 3, and wherein a break has occurred in a transmission
line through which multiframe data is transmitted, for
example, a break between the repeaters 52' and 53' in a
transmission line 56' in a direction from the terminal
station 51' to 55' as shown in Fig. 4.
In Fig. 8, an arrow ~l equals the arrow ~ in
Fig. 6. However, the multiframe data shown by ~z in
Fig. 6 can not be transmitted to the repeater 53 ' due
to the break in the transmission line 56' between the
repeaters 52' and 53' . Nevertheless, according to the
second embodiment of the present invention, the break
in the transmission line 56 ' between the repeaters 52 '
and 53 ' i s detected by the input line break detecting
means in the repeater 53 ' , and corresponding to the
this detection, the multiframe generating means in the
repeater 53' generates multiframe data, and the
information adding means in the repeater 53 ' writes the
current status of the repeater 53' in the frame which
includes the address of the repeater 53' among the
consecutive frames constituting the multiframe. Then the
multiframe data including the current status of the
repeater 53' , which is shown by ~ 3' in Fig. 8, is
sent out on the transmission line 56' . In the repeater
- -12- 1338448
54', the current status of the repeater 54' is written
in the multiframe data, and then the multiframe data
including the current status of the repeaters 53 ' and
54' , which is shown by ~ 4' in Fig. 8, is sent out
on the transmission line 56' and reaches the terminal
station 55' .
Namely, the other terminal station 55 ' can
collect the current status of the repeaters 53' and 54'
located downstream of the break point in the
transmission line 56' . Further, the time needed to
collect the current status of the repeaters 53 ' and 54
' is basically the same as in the first embodiment, i.e.,
"Y" as shown in Fig. 8.
Further, in the third embodiment of the present
invention, in addition to the process of the second
embodiment of the present invention, the information
adding means 6 in each of the repeaters 10 in Fig. 7,
also writes an alarm indication signal (AIS), which
indicates that a break has occurred in an input line,
20 as a part of the current status of the repeater 10, in
the aforementioned corresponding one of consecutive
frames in the transmitted multiframe, when a break in
the input line of a repeater 10 has been detected by the
input line break detecting means 11 in the repeater 10.
Therefore, according to the third embodiment of
the present invention, for example, in the construction
of Fig. 4, when a break occurs in a transmission line 56
' , in the direction of transmission from the terminal
stat;on 51' to the terminal station 55', between the
repeaters 52' and 53', the downstream terminal station
55 can determine the occurrence of a break between the
repeaters 52' and 53' in the transmission line, as a
part of the current status of the repeater 53' .
The first to third embodiments of the present
invention are applied to constructions wherein two
terminals are connected by a one-way transmission line
and a plurality of one-way repeaters are located along
~ -13- 133844~
the transmission line to transmit data, and therefore,
the current status of the repeaters is collected in only
one of the two terminal stations In particular, in the
first embodiment of the present invention, no
information reaches one of the terminal stations when a
break in the transmission line occurs between the
terminal stations.
The fourth to seventh embodiments of the present
invention, which will be explained in the following
text, are applied to constructions wherein two
terminals are connected by a pair of transmission lines
(i. e., by a two-way transmission line) and a plurality
of two-way repeaters are located along the pair of
transmission lines to transmit data, as shown in Fig. 1.
Therefore, in a normal operation, the current status of
the repeaters is collected in both terminal stations.
Figure 9 shows a basic construction of the fourth
embodiment of the present invention.
The construction for each direction of the data
transmission of the fourth embodiment of the present
invention shown in Fig. 9, corresponds to the
construction of Fig. 5. Accordingly, in the
construction of the fourth embodiment of the present
invention, as shown in Fig. 9, to enable the two-way
communication, each of the terminal stations 21 and 24
is provided with a multiframe generating means 26 and 29
and a multiframe data receiving means 27 and 28,
respectively, and each of the repeaters 23 has a
repeater means 32 and 35, an address detecting means 30
and 34, and an information adding means 31 and 33,
respectively, for each direction of data transmission,
and the terminal stations are connected by two
transmission lines 22 and 25.
The fourth embodiment of the present invention is
a system for monitoring the status of a plurality of
repeaters 23 l ocated along a pair of transmission lines
22 and 25 connecting two terminal stations 21 and 24 in
13384-48
--14--
both directions, wherein each of the terminal stations
21 and 24 comprises a multiframe generating means 26 and
29, which generates data in the form of a multiframe
consisting of a group of consecutive frames to be sent
to the other of the terminal stations 24 and 21, an
address of each of the repeaters 23 being included in
- the corresponding one of the consecutive frames; and
each of the repeaters 23 respectively comprises, for
each direction of transmission of the multiframe data,
an address detecting means 30 and 34 which detects the
own address of the repeater 23 i n one frame among the
consecutive frames, to determine a receipt of the
corresponding one of consecutive frames, and an
information adding means 31 and 33, which writes the
current status of the repeater in a frame which includes
the address of the repeater, when the repeater receives
the corresponding consecutive frame.
The operation and timing in the fourth embodiment
of the present invention mentioned above is explained
w i th reference to the timing chart of Fig. 8. Figure 8
shows the timing when the fourth embodiment of the
present invention is applied to the construction of Fig.
4, and wherein a break has occurred in a transmission
line through which multiframe data is transmitted, for
example, a break between the repeaters 52' and 53' in a
transmission line 56' in a direction from the terminal
station 51' to 55' as shown in Fig. 4.
In Fig. 8, an arrow ~1 equals the arrow ~1 in
Fig. 5. However, the multiframe data shown by c~ 2 in
Fig. 5 can not be transmitted to the repeater 53 ' due
to the break in the transmission line 56' between the
repeaters 52 ' and 53 ' . Nevertheless, according to the
second embodiment of the present invention, the break
in the transm;ssion line 56' between the repeaters 52'
and 53' is detected by the input line break detecting
means in the repeater 53', and corresponding to the
this detection, the multiframe generating means in the
-15- 133844~
repeater 53' generates multiframe data, and the
information adding means in the repeater 53' write the
current status of the repeater 53' in the frame which
includes the address of the repeater 53' among the
consecutive frames constituting the multiframe. Then the
multiframe data including the current status of the
repeater 53 ' , which is shown by ~ 3' in Fig. 8, is
sent out on the transmission line 56' . In the repeater
54' , the current status of the repeater 54 ' is written
in the multiframe data, and then the multiframe data
including the current status of the repeaters 53' and
54' , which is shown by ~ 4' in Fig. 8, is sent out
on the transmission line 56' , and reaches the terminal
station 55' .
lS According to the fourth embodiment of the present
invention mentioned above, when a break in the pair of
transmission lines has not occurred, the flow of data
and the timing in each direction are the same as in the
aforementioned first embodiment of the present
invention.
Figure 2 shows a timing of collecting the current
status information by the method for monitoring the
status of a plurality of repeaters in the fourth
embodiment of the present invention, compared with the
timing in the conventional method which was described
before.
In Fig. 2, the meanings of arrows ~l, ~ 2~ ~ 3~
and ~ 4, are substantially equal to the meaning of the
arrows ~I, ~z, ~ 3~ and ~ 4 in Fig. 6 for the
3~ first embodiment of the present invention, i.e., these
show multiframe data transmitted in the direction from
the terminal station S1 to 55, and the meaning of arrows
r " r z, r 3~ and r 4~ are also substantially
equal to the meaning of the arrows ~ " ~z, ~ 3,
and ~ 4 in Fig. 6 except that the arrows r " r z~ r
3, and r ~ in Fig. 2 correspond to the multiframe data
transmitted in the direction from the terminal station
~ -16- 1338448
55 to 51.
Therefore, as shown in Fig. 6, according to the
fourth embodiment of present invention, both the
terminal stations 51 and 55 receives the current status
of all repeaters 52 , 53 , and 54 in a time Y, which is
shorter than the time X needed in the polling method of
the prior art.
However, when a break in a transmission line has
occurred, for example, (see Fig. 1) between the
repeaters 52 and 53 in the transmission line 56 in Fig.
1, no data reaches the terminal station 55, as
mentioned in the first embodiment of the present
invention, but the current status of all of the
repeaters 52, 53, and 54 is collected by multiframe
data transmitted from the terminal station 55 to the
terminal station 51, and even the occurrence of a break
in the input line at the repeater 53, detec.ted by the
repeater 53, can be collected, as a part of the current
status of the repeater 53, by the multiframe data
transmitted from the terminal station 55 to the terminal
station 51, in the time Y.
Thus, in the fourth embodiment of the present
invention, when a break has occurred in one transmission
line only, although an upstream side terminal station
can collect the current status of all of the repeaters
betweem the terminal stations, a downstream side
terminal station 55 can not receive data.
Further, in the fourth embodiment of the present
invention, when a break occurs in both transmission
lines in both directions of data transmission, for
example, in the transmission lines 56 and 57 in Fig. 1,
no data reaches either of the terminal stations 51 and
55.
To solve the above problem in the fourth
embodiment of the present invention, the additional
means similar to the additional means added to the
aforementioned first embodiment to provide the
1338~1 18
-17-
aforementioned second embodiment of the present
invention, are added to the fourth embodiment of the
present invention, to provide the fifth embodiment
thereof.
Pigure 10 shows a basic construction of the fifth
embodiment of the present invention.
The construction for each direction of data
transmission of the fifth embodiment of the present
invention shown in Fig. 10 corresponds to the
construction of Fig. 7, and similar to the construction
of the fourth embodiment of the present invention
described before, in the construction of the fifth
embodiment of the present invention, as shown in Fig.
10, to enable the two-way communication, each of the
terminal stations 21 and 24 also has a multiframe
generating means 26 and 29 and a multiframe data
receiving means 27 and 28, respectively, and each of
the repeaters 40 also has a repeater means 32 and 35, an
address detecting means 30 and 34, and an information
adding means 31 and 32, respectively, for each
direction of data transmission, and further, the
terminal stations 21 and 24 are connected by two
transmission lines 22 and 25. In addition, in the
construction of the fifth embodiment of the present
invention as shown in Fig. 10, each of the repeaters 40
respectively further has an input line break detecting
means 41 and 44, and a multiframe generating means 42,
43, for each direction of data transmission.
The input line break detecting means 41 and 44 for
each direction of data transmission detects a break in
an input line in the corresponding direction.
The multiframe generating means 42 and 43 for each
direction of data transmission in each of the repeaters
40 basical]y has the same function as the multiframe
generating means 26 and 29 in the terminal stations 21
and 24, except that the multiframe ~enerating means 26
and 29 in each of the repeaters 40 operates only when a
-18- ~338448-
break in an input line in the corresponding direction is
detected in the repeater 40 by the input line break
detecting means 41 and 44 for the corresponding
direction of the data transmission.
Figure 3 shows the timing when the fifth
embodiment of the present invention is applied to the
construction of Fig. 4, and wherein a break has
occurred between the repeaters 52 and 53 in a
transmission line 56 in a direction from the terminal
station 51 to 55 as shown in Fig. 4, compared with the
conventional method described before.
In Fig. 3, an arrow cY~ equals the arrow cY, in
Fig. 2. However, the multiframe data shown by cY z in
Fig. 2 can not be transmitted to the repeater 53 due to
the break in the transmission line 56 between the
repeaters 52 and 53 . Nevertheless, according to the
fifth embodiment of the present invention, the break in
the transmission line 56 between the repeaters 52 and 53
is detected by the input line break detecting means in
the repeater 53, and corresponding to the this detection,
the multiframe generating means in the repeater 53
generates multiframe data, and the information adding
means in the repeater 53 writes the current status of
the repeater 53 in the frame which includes the address
of the repeater 53 among the consecutive frames
constituting the multiframe transmitted in the
direction from the terminal station 51 to 55. Then the
multiframe data including the current status of the
repeater 53, which is shown by ~ 3' in Fig. 3, is sent
out on the transmission line 56. In the repeater 54,
the current status of the repeater 54 is written in the
multiframe data, and then the multiframe data including
the current status of the repeaters 53 and 54, which is
shown by ~ 4 ' in Fi.g. 3, is sent out on the
transmission line 56, and reaches the terminal station
55.
The operation of the data transmission in the
l'g38448
--19--
direction from the terminal station 55 to 51, and
collection of the current status of the repeaters 52, 53,
and 54 by the terminal station 51, using the multiframes
shown by r -, r Z~ r 31 and r 4 in Fig. 3, is the
same as the operation shown by the same symbols in Fig.
.
Figure 11 shows the timing when the fifth
embodiment of the present invention is applied to the
construction of Fig. 4, and wherein a break has occurred
in both transmission lines 56 and 57, and for example,
between the repeaters 52 and 53, compared with the
conventional method described before.
In Fig. 11, the operation regarding the multiframe
data transmitted in the direction from terminal station
51 and 55 shown by the arrows ~l, ~ 3~, and ~ 4~ ,
is the same as the operation mentioned above with
reference to Fig. 3.
As readily understood from the similarity of the
abovementioned operation shown by the arrows ~l~ ~ 3
' , and ~ 4' and the operation shown by the arrows r ,
r 2 ~ and r 4 in Fig. 3, the operation for the
multiframe data transmitted in the direction from
terminal station 55 and 51 shown by the arrows r " r
z' , and r 4' ~ iS carried out in the same way as the
operation for the multiframe data transmitted in the
direction from terminal station 51 and 55 shown by the
arrows ~l~ ~ 3~ , and ~ 4 ~ .
Thus, when a break has occurred in one
transmission line, refer to Fig. 3, according to the
fifth embodiment of the present invention, even when a
break has occurred in both of the transmission lines
connecting the two terminal stations, for each
transmission line, the current status of the repeaters
located downstream of the break point is collected at
the downstream terminal station in the time Y, as shown
in Fig. 11.
In the sixth embodiment of the present invention,
-20- 13~448 -
in addition to the construction of the fifth embodiment
of the present invention, the information adding means
31 and 33 for each direction of data transmission also
writes an alarm indication signal (AIS) which indicates
the occurrence of a break in an input line in the
correaponding direction of data transmission, as a part
of the current status of the repeater, in the
corresponding one of consecutive frames ~the frame
corresponding to the repeater) in the multiframe
transmitted in the correaponding direction, when the
input line of the repeater, in the corresponding
direction of the data transmision, broke.
hccording to the sixth embodiment of the present
invention, when a break has occurred in a transmission
line, for example, in the direction of transmission from
the terminal station 51 to the terminal station 55
hetween the repeaters 52 and 53 as shown in Fig. 1, the
break is detected by an input line break detecting means
in the corresponding direction of transmission, and the
information for the break (an alarm indication signal)
is then written in the multiframe data in the
corresponding direction of transmission by the
information adding means corresponding to that
direction. Therefore, the terminal stations 55
downstream of the break can determine that a break in
the transmission line has occurred between the
repeaters 32 and 33, as a part of the current status
information.
Further, in the seventh embodiment of the present
invention, in addition to the construction of the fifth
embodiment of the present invention, the information
adding means for each direction of data transmission
also writes an alarm indication signal which indicates
the occurrence of a break in an input line in each
direction of data transmission, as a part of the current
status of the repeater, in the corresponding one of
consecutive frames (the frame corresponding to the
-21- 1338448
- repeater) in the multiframe transmitted in each
direction, when a break occurs in the input line of the
repeater in each direction of data transmision.
According to the seventh embodiment of the present
invention, when a break has occurred in a transmission
line, for example, in the direction of transmission from
the terminal station 51 to the terminal station 55
between the repeaters 52 and 53 as shown in Fig. 1, the
break is detected by an input line break detecting means
in the corresponding direction, and the information for
the break (an alarm indication signal) is then written
in the multiframe data in both directions by the
information adding means corresponding to both
directions of transmission. Therefore, both of the
terminal stations 51 and 55 can determine the
occurrence of a break in the transmission line between
the repeaters 52 and 53, as a part of the current status
of the repeater 53.
Consequently, in any embodiment of the present
invention, as shown in Figs. 4, 7, 9 and 10, all or a
part of the current status (the status information
which can be obtained under a line condition by each
embodiment of the present invention) of the repeaters
located along the transmission line, can be collected
almost in the time needed for multiframe data sent from
one terminal station to reach the other terminal
station through the transmission line connecting the
terminal stations and the repeaters, and the time
required for collecting status information to be
monitored is remarkably reduced, in comparison with the
conventional polling method.
133.~ i4~ -
-æ-
As a most prefferred embodiment of the present
invention, the seventh embodiment thereof is explained
hereinafter, because all functional means constituting
each of the first to sixth embodiments of the present
invention are included in this seventh embodiment, and
therefore, it will be clear that the first to sixth
embodiments of the present invention can be easily
modified in practice.
Figures 12 and 13 each show an example of the
format of the multiframe data transmitted in the present
invention.
The multiframe data shown in Fig. 12 consists of n
consecutive frames P1, F2, --Fi, --Fn, and each frame
Fi ~i=1~ n) provides twenty-four time slots for twenty-
four data channels DATAl, DATA2, DATAi, --DATA24,
and another three time slots for a frame synchronization
pattern FLM, a time slot for an address ADDi, and a
time slot for service bits SBi, where each time slot
consists of 6 bits.
The above time slot for an address ADDi for each
frame Fi (i=1~n) is a realization of one of the
aforementioned characteristics of the present invention,
i.e., in each time slot for an address ADDi for each
frame Fi (i=l~n) is written the address of the
corresponding repeater located along the transmission
line, and the time slot for service bits SBi (i=1 ~n)
is used to write the current stat~ls of the
corresponding repeater located along the transmission
line.
The multiframe data shown in Fig. 13 also consists
of n consecutive fra~es F1' , F2' , --Fi' , --Fn' ,
and each frame Fi' (i=1 ~n) provides thity-three time
slots for thirty-three data channels DATA1, DATA2, --
DATA;, --DATA32, and another four time slots for a
frame synchronization pattern FLM, and three time slots
for service bits SBik (k=1 ~3).
A more detailed construction of the above service
1338448-
-23-
bits SBik (k=1~3) is shown in Figure 14. As shown in
Fig. 14, in each frame Fi' (i=1~ n), all bits of the
above three time slots SBik (k=1 ~3) are combined, and
then the combined data as shown at the right of Fig. 14.
then includes an address region ADDR, a status region
STATUS, an alarm region ~LARM, an alarm indication
signal (AIS) region AIS, and a unit removal indication
region RMV, etc.
The above address region ADDR in each frame Fi' in
the multiframe of Fig. 13, plays the same role as the
time slot for an address ADDi in each frame Fi in the
multiframe of Fig. 12.
In the status region STATUS, the status of whether
the repeater is switched to the normal line or the
stand-by line is written by the information adding means
in each of the repeaters.
In the alarm region ALARM, the alarm status of the
repeater, e.g., a power failure, or a break in the
input lines (including the corresponding line and the
opposed line), etc., is written by the information
adding means in each of the repeaters.
In the alarm indication signal (AIS) region AIS,
the alarm status of whether the repeater has detected a
break in the input of the corresponding line, is
written by the information adding means in each of the
repeaters.
In the unit removal indication region RMV, the
status of whether or not any removable units which
constitute the repeater has been removed is written by
the information adding means in each of the repeaters.
Figure 15 shows a hardware construction of the
repeater used in the embodiments of the present
invention.
In Fig. 15, reference numerals 60 and 73 denote
optical signal transmission lines, 61 and 72 denote
signal receiving portions, 62 and 71 denote signal
sending portions, 63 and 70 denote demultiplexing
133844~ -
portions, 64 and 69 denote multiplexing portions, 65
and 68 denote information adding portions, 66 denotes an
MPU (microprocessor unit), and 67 denotes an alarm
information collecting portion.
The optical signal transmission line 60, s i gnal
receiving portion 61, s i gnal sending portion 62,
demultiplexing portion 63, multiplexing portion 64, and
information adding portion 65 are provided for the data
transmitted from left to right in the drawing, and
optical signal transmission line 73, signal receiving
portion 72, signal sending portion 71, demultiplexing
portion 70, multiplexing portion 69, and information
adding portion 68 are provided for the data transmitted
from right to left in the drawing.
lS The multiframe data in the form of optical signals
is transmitted on the transmission line 60, and
serially input to the signal receiving portion 61. The
optical signals are then transformed to corresponding
electric signals and input to the demultiplexing portion
63. In the demultiplexing portion, the aforementioned
address ADDi (i=1~n) in Fig. 12 or ADDR in Pig. 13,
and the other service bits SBi (i=1 ~n) in Fig. 12 or
SBik (i=1~n, k=1~3) in Fig. 13, are separated from
the other portion, i.e., DATA portion.
The above address ADDi (i=1 ~n) in Fig. 12 or
ADDR in Fig. 13, and the other service bits SBi (i=1 ~
n) in Fig. 12 or SBik (i=1~n, k=1~3) in Fig. 13, are
input to the information adding portion 65, wi th the
clock pulse first extracted from the above receiving
signals, and then supplied through the demultiplexing
unit 63 to all other portions of the repeater to
synchronize the operation therein.
The alarm information collecting portion 67
collects the alarm status of the repeater, e g., a power
alarm status, an optical alarm status, or a unit
removal alarm status, etc. from the corresponding
portions whereat the alarm statuses are detected. The
133-844~
--25--
object of the present invention is not the detection of
these alarm status, but how or how fast to send these
alarm statuses to the terminal stations, Since the
detection of these alarm status is a well known process,
e.g., the optical alarm status due to a break in the
input line can be detected by monitoring the level of
electric signals transformed from the optical input
signals at the signal receiving portion 61.
A concrete example of the construction of the
alarm information collecting portion 67 is shown in
Figure 16.
In Fig. 16, reference numeral 81 denotes an
address bus buffer, 82 denotes a decoder, 83 denotes an
alarm receiver, and 84 denotes a data bus buffer.
In the alarm receiver 83, various alarm status
si~nals, as mentioned above, are collected from the
abovementioned (alarm detecting) portions, and then
each of the collected status signals is then delivered
to the corresponding bit in the data bus, and finally,
is input to the MPU 66, under the control of the MPU 66
where the MPU 66 controls all portions of the repeater.
To carry out the above delivery, the MPU 66
outputs the required address signal through the address
bus, and the address signal is then input to the address
decoder 82 through the address bus buffer 81. The
output of address decoder 82 is used to control the
above alarm receiver 43.
A concrete example of the construction of the
information adding portion 65 i s shown in Figure 17.
In Fig. 17, reference numerals 91 and 92 denote
I/O memories, 92 denotes an address detecter, 93 denotes
a frame synchronizing circuit, 94 and 101 denote
parallel to serial transforming circuits, 95 denotes a
serial to parallel transforming circuit, 96 denotes an
interupt reguest controller, 98 denotes an address
generator, 99 denotes a frame controller, 100 denotes a
drop insert circuit, and 64 denoles the multiplexing
~ -26- 1~338448
portion shown in Fig. 15.
The aforementioned address ADDi (i=l~n) in Fig.
12 or ADDR in Fig. 13, and the other service bits SBi
(i=l ~n) in Fig. 12 or SBik (i=l~ n, k=1~ 3) in Fig.
13, separated from the DATA portion in the
demultiplexing portion 63, and the aforementioned clock,
are input to the frame synchronizing circuit 93, and
thereat, each of the address data and the service bits
is synchronized with the clock, and the address data is
then output in parallel to the address detector 92, and
both the address data and the service bits are
transformed again to serial data through the
parallel/serial transforming circuit 94.
The address detecter 92 holds the address of the
repeater itself, and detects the corresponding frame Fi
or Fi' including the same address, by comparing the
above input address ADDi or ADDR with the address of
the repeater itself.
When the address is not detected, all data
separated in the demultiplexing portion 63,
synchronized at the frame synchronizing circuit 93, and
then transformed to a serial form, is then transferred
through the serial to parallel transforming circuit 95,
the drop insert circuit 100, and the serial to parallel
transforming circuit 101, to the multiplexing portion 64.
The function of the drop insert circuit 100 is basically
an OR logic of the corresponding bits of the output of
the serial to parallel transforming circuit 95 and the
output of the l/O memory 97, mentioned later. Namely,
the address data and the service bits in the frames
which does not include the address of the repeater,
pass the information adding circuit 65, and are sent
out again in the same state as received.
When the address of the repeater is detected in
the address detecting portion 92, i.e., the
corresponding frame is detected in the multiframe data
received, the address detecter 92 outputs an interupt
133844~-
--Z1--
request signal to the interupt request controller 96.
Corresponding to the interupt request signals, the
interupt request controller 96 outputs an IR~ request
signal to the MPU 66.
The MPU 66 prepares the current status information
data to be sent to the terminal station by writing it
in the corresponding frame which includes the address
of the repeater, and outputs the current status
information data through the I/O memory 97, which acts
as a buffer, where the current status information data
prepared by the MPU 66 includes the alarm status
information collected in the alarm information
collecting portion 67, as mentioned before.
Corresponding to the IRQ request signal, the MPU
66 also controls the timing of the reading out of the
current status information that the status information
data, is input to the multiplexing portion 64 through
the drop insert circuit 100 at an appropriate timing,
and thus, the current status information data is output
in the corresponding time slot in the corresponding
frame in the multiframe data to be output to the
terminal station.
When a break in the input line is detected in the
signal receiving portion 61, the alarm information
showing an input line break, i.e., the optical alarm
status signal is transferred to the MPU 66 through the
alarm information collecting portion 67, while the
system clock which is supplied to all the portions of
the repeater to synchronize same, is switched to the
master clock generated in the master clock generator
usually provided in the demultiplexing portion 63 (not
shown).
Corresponding to the above alarm information, the
MPU 66 begins to control the information adding portion
65 and the multip]exing portion 64 so that multiframe
data is generated and sent out to the downstream side.
To ~enerate the addresses of all of the repeaters
1~8448
_
-28-
located along the transmi ss ion line, to be included in
the consecutive frames which constitute a multiframe,
the MPU 66 controls the address generator 98 in the
information adding portion 65 to generate the above
addresses. The timing of the output of each address is
given by the frame controller 99, which sends a timing
signal having a cycle time corresponding to the cycle
time of each frame in the multiframe so that the output
of the address generator 98, which is input to the
multiplexing unit 64, i s renewed for each frame. The
timing signal is generated by dividing the master clock
supplied from the demultiplexing portion 63.
The output of the address generator is also input
to the interupt request controller 96, and
correspondingly, the interupt request controller 96
outputs the IRQ request signal to the MPU 66.
Corresponding to the IRQ request signal, the MPU 66
controls the timing of the reading out of the current
status information data stored in the 1/0 memory 97 so
that the current status information data is input to the
multiplexing portion 64 through the drop insert circuit
100 at an appropriate timing, and thus the current
status information data is output at the corresponding
time slot in the corresponding frame in the multiframe
data to be output to the terminal station.
In the above, the construction consisting of
optical signal transmission line 60, signal receiving
portion 61, signal sending portion 62, demultiplexing
portion 63, multiplexing portion 64, information adding
30 portion 65, and alarm information collecting portion 67
and MPU 66, mainly corresponding to a data transmission
from left to right in the drawing, are described, but,
a similar description can be applied to the construction
consisting of optical signal transmission line 73,
signal receiving portion 72, signal sending portion 71,
demultiplexing portion 70, multiplexing portion 69,
information adding portion 68, and alarm information
1 338~48 -
collecting portion 67 and MPU 66, mainly corresponding
to a data transmission from right to left in the drawing.
In the above construction, when a break in the
input line of a transmission line is detected, the MPU
66 prepares the alarm indication signal (AIS) as a part
of the current status information to be sent to the
terminal station downstream of the transmission line in
which the break has occurred, and therefore, the
aforementioned sixth embodiment of the present
invention is realized.
Purther, in the above construction, when a break
in the input line of a transmission line is detected,
the MPU 66 prepares the alarm indication signal (AIS)
as a part of the current status information to be sent
to both terminal stations, indicating the transmission
line in which the break occurred. This is possible
because a plurality of (three) bits are provided for the
alarm indication signal (AIS) as shown in Fig. 14.
Accordingly, the aforementioned seventh embodiment of
the present invention is realized.
