Telephonic communications – Diagnostic testing – malfunction indication – or electrical... – Of centralized switching system
Reexamination Certificate
1999-02-01
2001-07-10
Nguyen, Duc (Department: 2643)
Telephonic communications
Diagnostic testing, malfunction indication, or electrical...
Of centralized switching system
C379S016000, C379S017000
Reexamination Certificate
active
06259768
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the invention
The present invention relates to a method of, and an apparatus for, carrying out a loopback test in an exchange. In particular, the present invention relates to a method of, and an apparatus for, carrying out a loopback test to diagnose devices that form a channel system of an exchange with the use of a loopback function provided for each of the devices.
2. Description of the Related Art
FIG. 9
shows devices that form a channel system of an exchange. The devices are a tester (TSTU)
9
-
1
, subscriber terminals
9
-
21
to
9
-
23
, individual devices (IND-A to IND-C)
9
-
31
to
9
-
33
, common devices (COM#
0
to COM#
2
)
9
-
41
to
9
-
43
, and a switching unit (SW)
9
-
5
.
Sub-highways (SHWO, SHW
1
)
9
-
61
and
9
-
62
are connected to the lower side of the common device
9
-
41
, and sub-highways (SHWO, SHW
1
)
9
-
63
and
9
-
64
are connected to the lower side of the common device
9
-
42
. Network highways (NHWO to NHW
2
)
9
-
71
to
9
-
73
connect the common devices
9
-
41
to
9
-
43
to the switching unit
9
-
5
. The devices also include unmounted subscriber devices IND-x and IND-y.
A mark “⊂” represents a loopback part through the drawings. Numerals attached to this mark like ⊂
0
, ⊂
1
, and ⊂
2
correspond to sub-highway or network highway numbers connected to the lower side of a given device. For example, “⊂
0
” is a loopback part for a sub-highway
0
(SHW
0
) or a network highway
0
(NHW
0
).
A mark “⊂C” is a loopback part for a highway connected to the higher side of a given device. A mark “⊂L” is a loopback part of an individual device for a subscriber channel end.
The tester
9
-
1
sends a test signal such as a voice signal or an ATM cell signal to devices to be tested, receives the test signal looped back by the devices, analyzes the received signal, and diagnoses the devices.
The terminals
9
-
21
to
9
-
23
terminate channels for subscribers A to C, respectively, and have each a loopback part for looping back a test signal.
The individual devices
9
-
31
to
9
-
33
are subscriber devices for interfacing the subscribers A to C with channels and have each a loopback part ⊂L for the subscriber and a loopback part ⊂C for the common device.
The common devices
9
-
41
to
9
-
43
are line concentrators for multiplexing signals from the individual devices and demultiplexing signals to the individual devices. The common devices have each loopback parts ⊂
0
and ⊂
1
for the individual devices, as well as a loopback part ⊂C for the switching unit
9
-
5
.
The switching unit
9
-
5
has a function of switching a main signal (communication information) transmitted through the network highways according to a destination and has loopback parts ⊂
0
to ⊂
2
for the network highways
9
-
71
to
9
-
73
.
Japanese Unexamined Patent Publication Nos. 2-97151, 3-104366, 4-157842, 4-207544, and 7-250076, for example, disclose a technique of testing and diagnosing devices arranged in an exchange by installing loopback parts in each device, sending a test signal from a tester, looping back the test signal at the loopback parts, analyzing the looped-back signal at the tester, and determining whether or not the devices are sound.
FIGS. 10 and 11
explain loopback tests carried out on devices that form a channel system of an exchange, according to a prior art. In
FIGS. 10 and 11
, the same parts as those of
FIG. 9
are represented with like reference numerals.
FIG. 10
tests a path from a tester
9
-
1
to a connection end of a common device
9
-
42
for a sub-highway
9
-
63
.
FIG. 11
tests a path from the tester
9
-
1
to a connection end of the common device
9
-
42
for a sub-highway
9
-
64
.
In
FIG. 10
, a path P
1
indicated with a thick line is set from the tester
9
-
1
to a loopback part ⊂
0
of the common device
9
-
42
for the sub-highway
9
-
63
through a common device
9
-
41
, network highway
9
-
71
, switching unit
9
-
5
, and network highway
9
-
72
, and then, from the loopback part ⊂
0
of the common device
9
-
42
to the tester
9
-
1
through the same route.
A loopback part cl of the switching unit
9
-
5
for the network highway
9
-
72
is activated, and the tester
9
-
1
transmits a test signal, which is looped back by the loopback part ⊂
1
of the switching unit
9
-
5
. The tester
9
-
1
receives the looped-back signal, analyzes it, and determines whether or not the path to the loopback part ⊂
1
of the switching unit
9
-
5
is sound.
The loopback part ⊂
1
of the switching unit
9
-
5
is released, and a loopback part ⊂C of the common device
9
-
42
is activated. The tester
9
-
1
sends a test signal, which is looped back by the loopback part ⊂C of the common device
9
-
42
. The tester
9
-
1
receives the looped-back signal, analyzes it, and determines whether or not the path to the loopback part ⊂C of the common device
9
-
42
is sound.
The loopback part ⊂C of the common device
9
-
42
is released, and the loopback part ⊂
0
of the common device
9
-
42
for the sub-highway
9
-
63
is activated. The tester
9
-
1
transmits a test signal, which is looped back by the loopback part ⊂
0
of the common device
9
-
42
. The tester
9
-
1
receives the looped-back signal, analyzes it, and determines whether or not the path to the loopback part ⊂
0
of the common device
9
-
42
is sound.
Thereafter, the path P
1
is released, and a path P
2
indicated with a thick line in
FIG. 11
is set from the tester
9
-
1
to the loopback part ⊂
1
of the common device
9
-
42
for the sub-highway
9
-
64
and from the same loopback part ⊂
1
to the tester
9
-
1
. The loopback part ⊂
1
of the common device
9
-
42
is activated, and the tester
9
-
1
transmits a test signal to this loopback part ⊂
1
. The tester
9
-
1
receives a looped-back signal from the same loopback part ⊂
1
, analyzes it, and determines whether or not the path to the loopback part ⊂
1
is sound.
FIG. 12
shows the steps of testing the common devices mentioned above. Steps
12
-
1
to
12
-
8
test the path P
1
of FIG.
10
. More precisely, step
12
-
1
sets an outgoing path from the tester
9
-
1
to the individual device
9
-
32
for the subscriber B through the common device
9
-
41
, switching unit
9
-
5
, and common device
9
-
42
.
Step
12
-
2
sets a return path from the individual device
9
-
32
to the tester
9
-
1
through the same route as the outgoing path.
Step
12
-
3
activates the loopback part ⊂
0
of the common device
9
-
42
so that a signal may be transferred from the outgoing path to the return path.
Step
12
-
4
instructs the tester
9
-
1
to send a test signal, receive a looped-back signal, and analyze the signal. Step
12
-
5
instructs the tester
9
-
1
to stop the test signal. Step
12
-
6
receives an analysis result from the tester
9
-
1
and examines it.
Step
12
-
7
releases the loopback part ⊂
0
of the common device
9
-
42
. Step
12
-
8
releases the outgoing and return paths, to complete the test of the path P
1
of FIG.
10
.
Steps
12
-
9
to
12
-
12
test the path P
2
of FIG.
11
. More precisely, step
12
-
9
sets an outgoing path from the tester
9
-
1
to the individual device
9
-
33
for the subscriber C through the common device
9
-
41
, switching unit
9
-
5
, and common device
9
-
42
.
Step
12
-
10
sets a return path from the individual device
9
-
33
to the tester
9
-
1
through the same route as the outgoing path.
Step
12
-
11
activates the loopback part ⊂
1
of the common device
9
-
42
so that a signal may be transferred from the outgoing path to the return path.
Step
12
-
12
executes the same processes as those executed in steps
12
-
4
to
12
-
8
to send a test signal, receive the test signal looped back by the loopback part ⊂
1
of the common device
9
-
42
, analyze the received signal, examine the analysis result, release the loopback part ⊂
1
of the common dev
Kato Tomomi
Mano Kosei
Ohnishi Kazuei
Saito Takamitsu
Takita Masatoshi
Fujitsu Limited
Helfgott & Karas P.C.
Nguyen Duc
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