Subscriber call simulator capable of testing new services of a telephone switching system

Connected to a telephone switching system through subscriber lines, a subscriber call simulator acts as a plurality of pseudo-subscriber's telephone sets. An input/output section inputs control procedure information for the pseudo-subscriber's telephone sets. Connected to the input/output section, a memorizing arrangement memorizes the control procedure information as stored information. By using the stored information, a control circuit controls the pseudo-subscriber's telephone sets. The control procedure information comprises a control procedure program and correspondence information stored in a procedure program memory and a correspondence information memory, respectively, both of which act as the memorizing arrangement.

BACKGROUND OF THE INVENTION 
This invention relates to a subscriber call simulator for use in testing a 
telephone switching system. 
In prior art, a telephone switching system only carries out a connecting 
service which connects a subscriber's telephone set of an originator with 
another subscriber's telephone set of a receiver which the originator 
dials. Such a connecting service is called a basic service. In order to 
test the basic service of the telephone switching system, use is made of a 
subscriber call simulator which makes the telephone switching system 
repeatedly carry out the basic service. In other words, the subscriber 
call simulator repeatedly carries out a basic operation which comprises 
call, dial number transmission, answer, speech confirmation, and 
disconnection, in the manner which will later be described in more detail. 
The subscriber call simulator is connected through subscriber lines to the 
telephone switching system. The subscriber call simulator acts as 
pseudo-subscriber's telephone sets. At any rate, a conventional subscriber 
call simulator only carries out the basic operation. 
With an appearance of an electronic switching system of a stored program 
control type, it has become possible to provide various new services, such 
as a call forwarding service, a three-way calling service, and so on in 
addition to the basic service. The conventional subscriber call simulator 
is disadvantageous in that it is impossible to carry out the test of the 
such new services. As a result, the subscriber's telephone sets must be 
directly put into operation on manually carrying out each new service by 
one who tests the new service. Inasmuch as each of those tests is a manual 
test, it takes a long time and a lot of man-hours to test the new 
services. On simultaneously carrying out the new services, the subscriber 
lines must be used without overlap. When the conventional subscriber call 
simulator is connected to another telephone switching system, reset must 
be made as regards all information indicative of, for example, dial 
numbers. Such a manual test is not efficient and can not shorten a test 
time interval. 
SUMMARY OF THE INVENTION 
It is an object of this invention to provide a subscriber call simulator 
which is capable of making a telephone switching system repeatedly carry 
out not only a basic service but also various new services. 
It is another object of this invention to provide a subscriber call 
simulator of the type described, which is capable of automatically testing 
the various new services. 
It is still another object of this invention to provide a subscriber call 
simulator of the type described, which can shorten a test time interval. 
Other objects of this invention will become clear as the description 
proceeds. 
On describing the gist of an aspect of this invention, it is possible to 
understand that a subscriber call simulator is connected through 
subscriber lines to a telephone switching system. The subscriber call 
simulator acts as pseudo-subscriber's telephone sets. 
According to this invention, the above-understood subscriber call simulator 
comprises inputting means for inputting control procedure information for 
the pseudo-subscriber's telephone sets, memorizing means connected to the 
inputting means for memorizing the control procedure information as stored 
information, and controlling means connected to the memorizing means and 
the pseudo-subscriber's telephone sets for controlling the 
pseudo-subscriber's telephone sets by using the stored information. 
On describing the gist of another aspect of this invention, it is possible 
to understand that a subscriber call simulator is connected to a telephone 
switching system through subscriber lines assigned with line numbers. The 
subscriber call simulator acts as pseudo-subscriber's telephone sets 
assigned with telephone numbers. 
According to this invention, the last-understood subscriber call simulator 
comprises inputting means for inputting a control procedure program for 
the pseudo-subscriber's telephone sets and correspondence information 
which makes the pseudo-subscriber's telephone sets correspond to the line 
numbers and the telephone numbers, procedure program memorizing means 
connected to the inputting means for memorizing the control procedure 
program, correspondence information memorizing means connected to the 
inputting means for memorizing the correspondence information, and 
controlling means connected to the procedure program memorizing means, to 
the correspondence information memorizing means, and to the 
pseudo-subscriber's telephone sets for controlling the pseudo-subscriber's 
telephone sets by using the control procedure program and the 
correspondence information stored in the procedure program memorizing 
means and the correspondence information memorizing means.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to FIG. 1, description will be made at first in order to 
facilitate an understanding of this invention as regards a conventional 
subscriber call simulator 10' for use in combination with a telephone 
switching system 20. 
As shown in FIG. 1, the conventional subscriber call simulator 10' is 
connected to the telephone switching system 20 through first through N-th 
subscriber lines 30-1, 30-2, 30-3, 30-4, . . . , and 30-N and first 
through N-th subscriber's circuits 31-1, 31-2, 31-3, 31-4, . . . , and 
31-N where N represents a predetermined number which is not less than 
three. 
The conventional subscriber call simulator 10' comprises first through N-th 
pseudo-subscriber's telephone sets 11-1, 11-2, 11-3, 11-4, . . . , and 
11-N which are connected to the first through the N-th subscriber lines 
30-1 to 30-N, respectively. The first through the N-th pseudo-subscriber's 
telephone sets 11-1 to 11-N are connected to a telephone control circuit 
12 in common. The telephone control circuit 12 is connected to a ringing 
detection circuit 13, a tone detection circuit 14, a multifrequency (MF) 
signal detection circuit 15, and a multifrequency signal generation 
circuit 16. The telephone control circuit 12 is controlled by a main 
control circuit 17 which is connected to an input/output (I/O) section 18. 
Description will be made below as regards an operation of the conventional 
subscriber call simulator 10' assuming without loss of generality that the 
first pseudo-subscriber's telephone set 11-1 calls the second 
pseudo-subscriber's telephone set 11-2. 
The main control circuit 17 receives a telephone number of the second 
pseudo-subscriber's telephone set 11-2 from the input/output section 18. 
On receiving a start indication from the input/output section 18, the main 
control circuit 17 controls the telephone control circuit 12 to put the 
first pseudo-subscriber's telephone set 11-1 in an off-hook condition. 
When the tone detection circuit 14 detects a dial tone, the telephone 
control circuit 12 controls the first pseudo-subscriber's telephone set 
11-1 to make the first pseudo-subscriber's telephone set 11-1 send through 
the first subscriber line 30-1 and the first subscriber's circuit 31-1 to 
the telephone switching system 20 the telephone number of the second 
pseudo-subscriber's telephone set 11-2 that is supplied from the 
multifrequency signal generation circuit 16. 
On receiving the telephone number of the second pseudo-subscriber's 
telephone set 11-2, the telephone switching system 20 sends a ringing 
signal to the second pseudo-subscriber's telephone set 11-2 through the 
second subscriber's circuit 31-2 and the second subscriber line 30-2. 
When the ringing detection circuit 13 detects the ringing signal for the 
second pseudo-subscriber's telephone set 11-2, the telephone control 
circuit 12 controls the second pseudo-subscriber's telephone set j 11-2 to 
put the second pseudo-subscriber's telephone set 11-2 in an off-hook 
condition. 
In order to confirm a speech path between the first and the second 
pseudo-subscriber's telephone sets 11-1 and 11-2, the main control circuit 
17 controls the telephone control circuit 12 by using the multifrequency 
signal detection circuit 15 and the multifrequency signal generation 
circuit 16 as follows. The second pseudo-subscriber's telephone set 11-2 
sends a tracer tone to the first pseudo-subscriber's telephone set 11-1 by 
using the multifrequency signal generation circuit 16. The first 
pseudo-subscriber's telephone set 11-1 detects the tracer tone by using 
the multifrequency signal detection circuit 15. Subsequently, the first 
pseudo-subscriber's telephone set 11-1 sends the tracer tone to the second 
pseudo-subscriber's telephone set 11-2 by using the multifrequency signal 
generation circuit 16. The second pseudo-subscriber's telephone set 11-2 
detects the tracer tone by using the multifrequency signal detection 
circuit 15. 
If the tracer tone is detected in both directions, the telephone switching 
system 20 normally carries out a switching connection processing for this 
call. Under the circumstances, the main control circuit 17 increments the 
number of completed calls by one. 
If the dial tone is not detected when five seconds lapse from a time 
instant at which the first pseudo-subscriber's telephone set 11-1 is put 
in the off-hook condition, the main control circuit 17 increments the 
number of incompleted calls by one. 
The main control circuit 17 supplies the number of the completed calls, the 
number of the incompleted calls, and the cause of the incompleted calls to 
the input/output section 18. 
Therefore, the conventional subscriber call simulator 10' has 
disadvantages, as pointed out in the preamble of the instant 
specification. 
Referring to FIG. 2, a subscriber call simulator 10 according to an 
embodiment of this invention is for use in combination with the telephone 
switching system 20, like in FIG. 1. 
In FIG. 2, the subscriber call simulator 10 is for connection to the 
telephone switching system 20 and comprises similar parts which are 
designated by like reference numerals and are operable as in the 
conventional subscriber call simulator 10' illustrated in FIG. 1. It 
should be noted that the subscriber call simulator 10 further comprises a 
procedure program memory 32 and a correspondence information memory 33 
which are connected to the input/output section 18 through the main 
control circuit 17. 
The first through the N-th subscriber lines 30-1 to 30-N are assigned with 
first through N-th line numbers, respectively. In the example being 
illustrated, the first through the N-th line numbers are equal to 0 
through (N-1), respectively. The first through the N-th 
pseudo-subscriber's telephone sets 11-1 to 11-N are assigned with first 
through N-th telephone numbers, respectively. 
The input/output section 18 acts as an inputting arrangement for inputting 
control procedure programs for the first through the N-th 
pseudo-subscriber's telephone sets 11-1 to 11-N and correspondence 
information. The correspondence information makes the first through the 
N-th pseudo-subscriber's telephone sets 11-1 to 11-N correspond to the 
first through the N-th line numbers and the first through the N-th line 
numbers. The control procedure programs and the correspondence information 
are supplied to the main control circuit 17. 
Supplied with the control procedure programs and the correspondence 
information, the main control circuit 17 stores the control procedure 
programs and the correspondence information in the procedure program 
memory 32 and the correspondence information memory 33, respectively. In 
other words, the procedure program memory 32 and the correspondence 
information memory 33 are for memorizing the control procedure programs 
and the correspondence information, respectively. 
A combination of the control procedure programs and the correspondence 
information is referred to control procedure information. Therefore, a 
combination of the procedure program memory 32 and the correspondence 
information memory 33 serves as a memorizing arrangement for memorizing 
the control procedure information as stored information. 
The main control circuit 17 reads the control procedure programs and the 
correspondence information from the procedure program memory 32 and the 
correspondence information memory 33 and then controls the first through 
the N-th pseudo-subscriber's telephone sets 11-1 to 11-N through the 
telephone control circuit 12 by using the control procedure programs and 
the correspondence information in the manner which will later becomes 
clear. At any rate, a combination of the main control circuit 17 and the 
telephone control circuit 12 serves as a controlling arrangement for 
controlling the first through the N-th pseudo-subscriber's telephone sets 
11-1 to 11-N by using the control procedure programs and the 
correspondence information. 
Turning to FIG. 3, the correspondence information memory 33 is loaded with 
the correspondence information as shown in a rectangular outline indicated 
by the reference numeral 33. It will be assumed that the predetermined 
number, namely, N is equal to ten. In FIG. 3, A, B, C, D, E, F, G, H, I, 
and J are shown in a leftmost column to indicate the first through the 
tenth pseudo-subscriber's telephone sets 11-1 to 11-10 which correspond to 
the first through the tenth line numbers, 0 to 9, and the first through 
the tenth telephone numbers, 82-1234, 82-1235, 82-1236, 82-1237, 82-1238, 
82-1239, 82-1240, 82-1245, 82-1246, and 82-1247. 
Turning to FIG. 4, the procedure program memory 32 is loaded with the 
control procedure programs as shown in a block outlined by dash-dot lines 
and indicated by the reference numeral 31. In the example being 
illustrated, the control procedure programs are equal in number to three 
and are called first through third control procedure programs 32-1, 32-2, 
and 32-3. The first control procedure program 32-1 is a control procedure 
program for a call forwarding service by using the first through the third 
pseudo-subscriber's telephone sets 11-1, 11-2, and 11-3 which are 
indicated by A, B, and C. The second control procedure program 32-2 is a 
control procedure program for a three-way calling service by using the 
fourth through the seventh pseudo-subscriber's telephone sets 11-4, 11-5, 
11-6, and 11-7 which are indicated by D, E, F, and G. The third control 
procedure program 32-3 is a control procedure program for a call waiting 
service by using the eighth through the tenth pseudo-subscriber's 
telephone sets 11-8, 11-9, and 11-10 which are indicated by H, I, and J. 
Referring to FIG. 5, description will be made as regards operation executed 
in accordance with the first control procedure program 32-1 which the 
subscriber call simulator 10 carries out in cooperation with the telephone 
switching system 20. It will be presumed that the second 
pseudo-subscriber's telephone set 11-2 is provided with function of the 
call forwarding service. In the first control procedure program 32-1, the 
first pseudo-subscriber's telephone set A or 11-1 dials the second 
pseudo-subscriber's telephone set 11-2 which is indicated by B and which 
has the telephone number of 82-1235 to terminate the third 
pseudo-subscriber's telephone set 11-3. The first control procedure 
program 32-1 is described by predefined character codes as follows: 
DT: a dial tone (a continuous tone having a frequency of 400 Hz), 
RBT: a ringback tone (an intermittent tone which has a frequency of 600 Hz 
and continue an intermittent stop during four seconds), 
RGT: a ringing tone (an intermittent tone having a frequency of 20 Hz and 
continues two seconds with an intermittent stop during four seconds), and 
TRACE: a tracer tone (a continuous tone having a frequency of 800 Hz). 
At a first step S1, the main control circuit 17 indicates call of the first 
pseudo-subscriber's telephone set 11-1 indicated by A. Thereupon, the 
first pseudo-subscriber's telephone set 11-1 is put in an off-hook 
condition. The first step S1 is followed by a second step S2. 
At the second step S2, the main control circuit 17 indicates that the first 
pseudo-subscriber's telephone set 11-1 carries out a monitor operation of 
the dial tone by using the tone detection circuit 14 during three seconds. 
If the dial tone is detected by the tone detection circuit 14, the second 
step S2 proceeds to a third step S3. Otherwise, the operation comes to an 
end. 
At the third step S3, the main control circuit 17 indicates that the first 
pseudo-subscriber's telephone set 11-1 sends a multifrequency signal 
having the telephone number of the second pseudo-subscriber's telephone 
set 11-2 by using the multifrequency signal generation circuit 16. The 
third step S3 is succeeded by a fourth step S4. 
At the fourth step S4, the main control circuit 17 indicates that the first 
pseudo-subscriber's telephone set 11-1 carries out a monitor operation of 
the ringback tone by using the tone detection circuit 14 during ten 
seconds and the third pseudo-subscriber's telephone set C or 11-3 carries 
out a monitor operation of the ringing tone by using the ringing detection 
circuit 13 during ten seconds. If the ringback tone and the ringing tone 
are detected by the tone detection circuit 14 and the ringing detection 
circuit 13, the fourth step S4 is followed by a fifth step S5. Otherwise, 
the operation comes to the end. 
At the fifth step S5, the main control circuit 17 indicates an answer of 
the third pseudo-subscriber's telephone set 11-3. Thereupon, the third 
pseudo-subscriber's telephone set 11-3 is put in an off-hook condition. 
The fifth step S5 proceeds to a sixth step S6. 
At the sixth step S6, the main control circuit 17 indicates that the third 
pseudo-subscriber's telephone set 11-3 sends the tracer tone by using the 
multifrequency signal generation circuit 16 during five seconds. In the 
meantime, the first pseudo-subscriber's telephone set 11-1 carries out a 
monitor operation of the tracer tone by using the multifrequency signal 
detection circuit 15 during five seconds. If the tracer tone is detected 
by the multifrequency signal detection circuit 15, the sixth step S6 is 
succeeded by a seventh step S7. Otherwise, the operation comes to the end. 
At the seventh step S7, the main control circuit 17 indicates that the 
first pseudo-subscriber's telephone set 11-1 sends the tracer tone by 
using the multifrequency signal generation circuit 16 during five seconds. 
Meanwhile, the third pseudo-subscriber's telephone set 11-3 carries out a 
monitor operation of the tracer tone by using the multifrequency signal 
detection circuit 15 during five seconds. If the tracer tone is detected 
by the multifrequency signal detection circuit 15, the seventh step S7 is 
followed by an eighth step S8. Otherwise, the operation comes to the end. 
At the eighth step S8, the main control circuit 17 indicates disconnection 
of the first pseudo-subscriber's telephone set 11-1. Thereupon, the first 
pseudo-subscriber's telephone set 11-1 is put in an on-hook condition. The 
eighth step S8 proceeds to a ninth step S9. 
At the ninth step S9, the main control circuit 17 indicates disconnection 
of the third pseudo-subscriber's telephone set 11-3. Thereupon, the third 
pseudo-subscriber's telephone set 11-3 is put in the on-hook condition. 
The ninth step S9 proceeds to the end. 
Turning to FIG. 6, description will be made as regards a case where another 
telephone switching system should be tested instead of the telephone 
switching system 20. Under the circumstances, the first through the N-th 
pseudo-subscriber's telephone set 11-1 to 11-N are assigned with the first 
through the N-th telephone numbers which are different from those as shown 
in FIG. 3. Therefore, the input/output section 18 (FIG. 2) inputs new 
correspondence information alone. The new correspondence information is 
stored in the correspondence information memory 33 (FIG. 2) by the main 
control circuit 17 as shown in a rectangular block indicated by the 
reference numeral 33. What should be noted in this connection is that it 
is unnecessary to change the control procedure programs stored in the 
procedure program memory 32 (FIG. 2). In FIG. 6, for example, the first 
pseudo-subscriber's telephone set A or 11-1 corresponds to the first line 
number 0 and the first telephone number, namely, 461-3251. 
While this invention has thus far been described in conjunction with only 
one preferred embodiment thereof, it will now readily be possible for 
those skilled in the art to develop various other embodiments of this 
invention. For example, the procedure program memory memorizes only one 
control procedure program.