FR2646743A1 - Process for testing telephone handset functionality - Google Patents

Abstract

The telephone terminal employs internal management electronics 20 and comprises at least one unit 1, 2, n for detecting frequencies from the audible range which are received by the telephone line for management. On lifting the handset 6, an electro-acoustic loop is created comprising the earpiece and the microphone of the handset at one F of the said frequencies, the frequency F is detected by one of the detection units 1, 2, n in order to permit telephone communication.

Description

The invention applies to the field of telephony and relates more particularly to a method for automatically testing the functionality of telephone terminals developed and having internal management electronics such as telephone equipment made available to the public and commonly called payphones.

Although benefiting from a design having the concern of reliability and a particularly robust realization. payphones are subject to acts of vandalism, the effects of which can be visible but also hidden, the effects of these acts being added to the always possible breakdowns of the equipment. all the more so since the said effects are not systematically frank as would be that of an electrical discontinuity which does not allow telephone communication
The user of equipment thus defective.

could, if he does not notice the defect of the device, as would be that caused by a tearing of the handset. to commit a sum of money such as coins or a telephone card credit, to establish the telephone connection with a correspondent, but not being able to converse owing to reciprocal inaudibility of the two correspondents or only one of them; the amount of money incurred during the trip would be lost.

The present invention provides a solution.

interesting to this problem and presents for this purpose a method of testing telephone handset functionality characterized by the fact that it uses means for concomitantly testing the reception and transmission means of the telephone terminal advantageously the method implements a loop electro-acoustic including earpiece and microphone of the telephone terminal handset.

The invention will be better understood with the aid of the following description of the preferred example of application of the method. with reference to the accompanying drawings in which
Figure 1 shows schematically the circuits
entrance to a payphone.

Figure 2 shows in more detail the
circuit used by the method of one invention.

The payphone is connected to the LT telephone line from the telephone network. for example a connection unit or a telephone exchange.

This line LT allows the transmission of telephone messages as well as various signals relating to the management of the equipment. said signals are emitted in the form of frequencies belonging to the audible range and generally 440 Hz. 2lpO Hz and 12,000 Hz. and are detected by a set of detection blocks 1. 2. n - for example PLL circuits ref. LMC 567 CN manufactured by National Semiconductor.

These detection blocks each address the microprocessor 20 managing the public phone. logical information representative of the presence or absence of their respective detection frequencies.

A line interface circuit 4 includes a 2-wire / 4-wire transformer block. 5. connected to the telephone handset 6 comprising an earpiece 7 and a microphone 8.

A circuit 9 known as headphone inhibition is mounted in bypass on the line of the headphone; it acts as an electronic switch, controlled by the management microprocessor, it interrupts the earphone circuit during certain operating phases of the public phone - for example during the retransmission of alarms.

According to the method of the invention. when the handset is lifted 6. the microprocessor 20 controls the input 10 of the earphone inhibition circuit 9 to the moon. F. of the frequencies detected by the detection blocks 1, 2.

not; for example at 440 Hz, circuit 9 acting as an electronic switch will retransmit this frequency of 440 Hz to the earpiece 7. which will transform it into a sound wave 12 picked up by the microphone 8, which will reinject this same frequency F into the transformation block 2 son / 4 son. 5. through an amplifier 13; an electro-acoustic loop at the control frequency F is thus created when the telephone handset - payphone connections are correct and the telephonometric performance, that is to say the reception and resignation qualities of the telephone handset 6 are also correct and in this case the signal F will be retransmitted to the corresponding detector 1, 2, n, which detector will send to the microprocessor 20 a logic signal authorizing the telephone communication.

In the case where the telephone receiver telephone link is defective, or in the case of insufficient telephonometric performance, the electro-acoustic loop would not be established, no signal would be received by the appropriate detector and the
microprocessor 20 would not receive a telephone communication authorization order.

In practice, the proper functioning test can be carried out in a duration substantially less than a second. it is therefore finished before the user has brought the handset to his ear.

The present invention makes it possible to test the functionality of the telephone handset during each communication, without requiring additional components for the telephone terminal. only the programming of its management microprocessor is modified accordingly.

Claims (3)

 1- Method for testing the functionality of a telephone handset (6) of a telephone terminal comprising a management microprocessor (20). a line interface circuit (4) at least one frequency detector (1, 2, n), a headphone muting circuit (9), characterized in that an electro-acoustic loop is created å a frequency F of the audible range, the loop comprising the earphone inhibition circuit (9) controlled at this frequency F by the microprocessor (20) the earpiece (7) and the microphone (8) of the handset (6) . the line interface circuit (4) the frequency F is detected by the detector (1.2, n) corresponding to it, said detector delivers a logic signal authorizing the establishment of telephone communication.  2- A method of testing the functionality of a telephone handset (6) of a telephone terminal according to claim 1 in which the frequency F is one of the frequencies normally received through the telephone line by the telephone terminal for its management .  3- A method of testing the functionality of a telephone handset (6) of a telephone terminal according to claim 2 wherein the frequency F is 440 Hz or 2,100 Hz or 12,000 Hz.