Testing telecommunications equipment

A system for testing telecommunications equipment located at two sites includes a set of test instruments located at each site, a local test controller located at each site for controlling the test instrument at that site, and a master test controller connected to the local test controller by data links. Each test controller is provided with a clock and the clocks are synchronized by a common timing signal. The master test controller is arranged to transmit test instructions to, and receive test results from, the local test controllers.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a system for, and a method of, testing 
telecommunications equipment. 
2. Related Art 
In U.S. Pat. No. 4,910,760, there is described a system for testing 
telecommunications equipment comprising a local test controller for 
controlling test instruments and a master test controller for controlling 
the local test controller. Similar systems are described in U.S. Pat. No. 
4,937,850 and U.S. Pat. No. 4,001,559. Where a master test controller 
controls one or more local test controllers, it has been found that some 
tests require synchronisation between the test controllers. However, this 
problem is neither identified nor solved in any of these three prior art 
documents. 
SUMMARY OF THE INVENTION 
According to this invention, there is provided a system for testing 
telecommunications equipment, said system comprising a master test 
controller, at least one local test controller, a test instrument 
associated with the or each local test controller and arranged to be 
controlled thereby, and means for transmitting data between the master 
test controller and the or each local test controller, said data being 
test instructions transmitted by the master test controller to the or each 
local test controller and test results received by the master test 
controller from the or each local test controller, each test controller 
being provided with a clock having an antenna for receiving a common radio 
timing signal. 
By providing a clock having an antenna for receiving a common radio timing 
signal for each test controller, the operation of the test controllers may 
be accurately synchronised.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
The drawing of FIG. 1 shows two sites, namely site A and site B, at which 
telecommunications equipment is located. The equipment located at each 
site may comprise, for example, a switch, one or more multiplexers, a 
computer for operating the switch and equipment for providing information 
which may be used for charging purposes. The two sites are connected by a 
traffic carrier 10 and the sites are connected to further sites, not 
shown, by further traffic carriers 11. The traffic carriers 10, 11 may be, 
for example, optical fibres or microwave links. 
Sites A and B are provided, respectively, with a set of test instruments 
12, 13. Each test instrument is arranged to make tests at one or more 
points in the equipment located at its site. Sites A and B are also 
provided, respectively, with local test controllers 14, 15 each of which 
is arranged to control the test instruments 12, 13 located at its site. 
The local test controllers 14, 15 are provided with clocks 16, 17. 
The system also includes a master test controller 20 which may be located 
at one of the sites A or B or at another convenient location. Data may be 
transmitted between the master test controller 20 and the local test 
controllers 14, 15 through data links 21, 22. By way of example, the links 
21, 22 may be dedicated traffic carriers or may form part of a public 
telecommunications network. The master test controller 20 is provided with 
a clock 23. 
Each of the clocks 16, 17 and 23 is provided with an antenna 24 for 
receiving a common timing signal in the form of the International Time 
Standard. The International Time Standard is transmitted worldwide from 
the Internal Time Bureau in Paris via satellite. Thus, the International 
Time Standard is used to synchronise the clocks 16, 17 and 23. Other time 
sources, for example, a portable clock or off-air receivers may be used. 
Each of the clocks 16, 17 and 23 is a type RCC8000 clock manufactured by 
Radiocode (UK) Ltd, of Radiocode House, Jennings Road, Penryn, Cornwall, 
England. 
The master test controller 20 has a memory 25 which contains it operating 
program. The operating program includes a module for instructing the local 
test controllers 14, 15 to initialise the test instruments 12, 13, modules 
for instructing the local test controllers 14, 15 to perform various 
tests, modules for logging the results of the tests, and modules for 
correlating, filtering and analyzing the results. 
The test system may be used to perform a wide range of tests. For example, 
it may be used to monitor the integrity and speed with which messages are 
transmitted from site A to site B. In order to achieve this, the master 
test controller 20 instructs the local test controller 14 to instruct an 
appropriate one of test instruments 12 to transmit defined message at 
preset times to site B. It also instructs the local zest controller 15 to 
instruct an appropriate one of test instruments 13 to monitor the 
integrity with which each message is received and the time of its receipt. 
The local test controller 15 is also instructed to send the results back 
to the master test controller 20. The master test controller 20 logs and 
analyzes the results. Thus, the integrity of transmission of a large 
number of messages may be tested. Also, because the clocks 16, 17 and 23 
are synchronised, the transmission period for each message may be 
determined accurately. The remote test instruments may also be operated 
interactively via the master test controller 20. 
Other uses of the test system shown in FIG. 1 include testing the accuracy 
with which messages are routed, performance measurements, testing the 
integrity of new equipment in a telecommunications network and the 
accuracy and operation of charging equipment. The operating program for 
the master test controller 20 is arranged to present the analysis of the 
results in a form which may be easily and rapidly understood by its human 
operator. Because the test system performs and analyzes tests 
automatically, results are achieved quickly and with minimum expenditure 
of time by its operator. 
Although not shown in FIG. 1, the test system could be expanded so that the 
master controller 10 controls local test controllers, and hence test 
instruments, at more than two sites. Also, the local test controllers and 
test instruments controlled by them can be moved from site to site, as 
required, while the master zest controller remains at the same site. 
Referring now to FIG. 2, there is shown a test system for testing the 
accuracy of charging equipment located at a local exchange forming part of 
a public switched telecommunications network. 
In FIG. 2, the public telecommunications network is indicated generally at 
20. The public telecommunications network 30 is of generally conventional 
construction and comprises a set of interconnected trunk exchanges, each 
of which is connected to one or more local exchanges which in turn are 
connected to customers' equipment. The local and trunk exchanges may be, 
for example, System X exchanges manufactured by GEC Plessey 
Telecommunications. The public telecommunications network 30 can support 
both voice and ISDN calls. FIG. 2 shows two of the local exchanges and 
these are indicated by reference numerals 32, 34. 
The public telecommunications network 30 includes a network analyzer 36 
which is operated by a computer 38. 
The test system comprises a master test controller 40, and two local test 
controllers 42, 44, which are located, respectively, at local exchanges 
32, 34. The master test controller 40 and the local test controllers 42 
and 44 are each implemented as a computer and these test controllers are 
generally similar to those shown in FIG. 1. The test controllers 40, 42 
and 44 are provided with clocks 45, 47 and 49, which are similar to the 
clocks 16, 17 and 23 in FIG. 1. 
In the present example, the master test controller 40 is located at a site 
which is remote from local exchanges 32 and 34. In order to pass data, 
including test instructions and test results, between the master test 
controller 40 and the local test controllers 42 and 44, these test 
controllers are provided with modems 52, 54 and 56. Data is transmitted 
between modem 52 and modems 54 and 56 over an RS232 connection which, 
conveniently, may be made through a public telecommunications network. 
The local test controllers 42, 44 control, respectively, call senders 46 
and 48. The call senders 46, 48 are connected, respectively, to the local 
exchanges 32, 34. Each call sender 46, 48 can make and receive calls via 
its local exchange. Thus, the call sender 46 can make a call via local 
exchange t2 to a destination number connected to another local exchange or 
to a destination number served by local exchange 32. If desired, the call 
sender 46 can send a call to itself via local exchange 32, using one 
exchange line as the outgoing line and another line as the incoming line. 
The call sender 48 has similar capabilities. Each of the call senders 46, 
48 is a call sender manufactured by Rotadata Limited of Bateman Street, 
Derby, England and sold under The product name KESTREL. 
The computer 38 is provided with a modem 58 for transmitting data, using an 
RS232 connection, to modem 52, which in turn transmits the data to the 
master test controller 40. 
Each of the local exchanges 32, 34 is provided with equipment for providing 
charging data relating to each call made by the customers of that 
exchange. Each of the local test controllers 42, 44 has access to this 
charging data and can transmit it, on a selective basis, to the master 
test controller 40. 
In order to test the accuracy of the charging equipment located at local 
exchange 22, the master test controller 40 instructs the local test 
controller 42 to cause the call sender 46 to make a series of calls at 
preset times and having preset durations to call sender 48. It also 
instructs the local test controller 44 to cause the call sender 48 to 
monitor each of these calls. The local test controllers 42, 44 send the 
results of the calls to the master test controller 40 and, in addition, 
the local test controller 42 sends the charging data for each call to the 
master test controller 40. The master test controller 40 then analyzes the 
results on a call-by-call basis. For each call, it specifically checks 
that the results from the local test controller 42 show that the call was 
made at the preset time with the preset duration, that it was received by 
the call sender 48 at the preset time and for the preset duration, and 
that the charging data for that call retrieved from the charging equipment 
for Local exchange 32 has accurately recorded the charge for the call. In 
the analysis, the maser test controller 40 records any differences between 
the results from local test controller 42 and the results from local test 
controller 44 and any difference between the charge for the call as 
calculated from the results from local test controller 42 for that call 
and from the data retrieved from the charging equipment. 
The network analyzer 36 provides data on each call relating to its set up. 
Where the results from local test controller 42 and 44 differ for a 
particular call, the reason for this may be apparent from the data 
obtained from network analyzer 35. 
Referring now to FIG. 3, there is shown the routine used by master test 
controller 40 for establishing a series of calls. After entering this 
routine, in a step S10, the master controller 40 asks the operator for the 
destination number for a call. This number is entered by the operator. 
Next, in a step S11, the master test controller 40 asks the operator for 
the preset time for the call and the operator enters this data. Then, in a 
step S12, the master test controller 40 asks the operator for the duration 
of the call and the operator enters this data. 
In a step S13, the master test controller 40 asks the operator if he wishes 
to establish any further calls. If the operator does wish to establish a 
further call, the routine returns to S10. If the operator does not wish to 
establish any further calls, the routine continues with a step S14. In 
this step, the master test controller downloads instructions to the local 
test controller 42 to make the calls and instructions to the local test 
controller 44 to check that the calls are received. 
Although in the example given above, the test system is used to test the 
accuracy of the charging equipment located at local exchange 32, it is to 
be appreciated that it can also be used to check the charging equipment 
located at local exchange 34. In this case, the master controller 40 
instructs the local test controller 44 to make the calls and the local 
test controller 42 to test the results of the calls. If it is desired to 
test the accuracy of charging equipment located at other exchanges, this 
may be achieved by moving one of the local test controllers 42, 44 
together with its call sender and modem to that exchange. Alternatively, 
the other exchange may be provided with its own dedicated call sender and 
local test controller. 
Referring now to FIG. 4, there is shown another test system for testing a 
telecommunications network. The telecommunications network shown in FIG. 4 
comprises four fully interconnected switches 60, 62, 64 and 66. Each of 
the switch 60, 62, 64, 66 is a switch of the type known as a service 
switching point and, in the present example, each of these switches in an 
AXE10 switch manufactured by Ericcson Telecommunications. The switches 60, 
62, 64, 66 have access to a service control point, not shown, which 
contains data, such as number translation data, to support the services 
provided by the telecommunications network. 
The switches 60, 62, 64, 66 are connected, respectively to multiplexers 68, 
70, 72, 74. By way of modification each switch may be connected to more 
than one multiplexer. The multiplexers 68, 70, 72, 74 are connected to 
private automatic branch exchanges (PABX) belonging to the customers of 
the network. For reasons of simplicity, only four PABXs are shown in FIG. 
4 and these are denoted by reference numerals 76, 78, 80, 82. 
The test system comprises a call sender 90 controlled by a local test 
controller 92, which in turn is controlled by a master test controller 94. 
The call sender 90 is of the same type as call sender 76 shown in FIG. 2 
and the local test controller 92 and the master test controller 94 of the 
same general construction as the local test controller 42 and the master 
test controller 40 shown in FIG. 2. Each of the test controllers 92, 94 is 
provided with a clock similar to the clocks 45, 47 and 49 and these two 
test controllers are provided with modems so that they can be connected by 
an RS232 connection. Alternatively, the master test controller can be 
located with the local test controller 92 and connected to it directly. 
The call sender 90 and the local test controller 92 are located at the 
site of multiplexer 68 and the call sender 90 is connected to the 
multiplexer 68 for the purpose of making and receiving calls. 
The PABXs 76, 78, 80 and 82 are provided, respectively, with answering sets 
96, 98, 100, 102, and each of these answering sets is manufactured by, and 
available from, Rotadata Limited. 
In order to test the operation of the telecommunications network shown in 
FIG. 4, the master test controller 94 instructs the local test controller 
92 to cause the call sender 90 to make a series of calls at preset times 
to the answering sets 96, 98, 100, 102. The local test controller 92 then 
returns the results of these calls to the master test controller 94. The 
master test controller then analyzes them in order to assess the 
performance of the network. If desired, the master test controller can 
transmit the results to a network management centre, not shown. 
By way of modification, the test system may include answering machines 
which are connected directly to one or more of the multiplexers 68, 70, 
72, 74. 
Referring now to FIG. 5, there is shown a modification to the test system 
shown in FIG. 4. In FIG. 5, the telecommunications network takes the same 
general form as shown in FIG. 4 and like parts are being denoted by the 
same reference numerals. Although not shown in FIG. 4, the multiplexers 
68, 70, 72 and 74 are connected to PABXs. 
The test system comprises two call senders 110, 112, which are controlled, 
respectively, by local test controller 114, 116. The test system also 
includes two master test controllers 118, 120. Although not shown, the 
test system also includes answering machines which are connected either to 
PABXs or directly to the multiplexers. The call senders 110, 112 are of 
the same type as the call senders 46 shown in FIG. 2, the local test 
controllers 114, 116 are of the same general form as the local test 
controller 42 shown in FIG. 2, and the master test controllers 118, 120 
are of the same form as the master test controller 40 shown in FIG. 2. 
Although not shown the test controllers are provided with clocks similar 
to the clock 47 shown in FIG. 2. 
The call sender 110 and the local test controller 114 are located at the 
same site as multiplexer 68 and the call sender 110 is connected to this 
multiplexer 68 for making and receiving calls. Similarly, the call sender 
112 and the local test controller 116 are located at the site of 
multiplexer 74 and the call sender 112 is connected to multiplexer 74 for 
the purpose of making and receiving calls. The test controllers are 
provided with modems and both local test controllers 114, 118 can 
communicate with both master test controllers 1l8, 120 via an RS232 
connection. The master test controllers 118, 120 are located remotely from 
each other. 
In order to test the network, either of the master test controllers 118, 
120 can send instructions to the local test controllers 114, 116. These 
instructions may take the form of instructing one of the local test 
controllers to cause its call sender to make a series of calls to 
answering machines. Alternatively, the instructions may take the form of 
instructing one of the local test controllers to cause its call sender to 
make calls to the call sender controlled by the other local test 
controller. 
The test system of FIG. 5 provides the advantage that an operator can test 
the network either from the location of master test controller 118 or the 
location of master test controller 120.