IE42719B1 - Signalling system for manually established calls from coinbox stations - Google Patents

Description

This invention relates to signalling systems for manually established calls from coinbox stations.

Coinbox stations connected to the public network will normally have the possibility of calling operators' stations. In some cases this can be prevented by special couplings in the exchange.

In the manual establishment of calls from coinbox stations some problems arise.

It should be possible to pay the charge in such a manner that the operator can check ihe amount deposited, and the operator should be able to ascertain whether such payment should be demanded, or the amount is to be charged to account. Since coinbox stations are usually arranged for automatic self selection with automatic debiting, an amount balance register is usually provided which controls the collection of coins. In some cases there is further a possibility of disposing of a non-used balance for a new call. In such coinbox stations amounts which are deposited for payment of a manually established call should not be registered in the balance register, and moreover coin identification should be transmitted.

When coinbox stations are rented, they will usually be equipped with a so-called holder's key which enables the holder to make calls without depositing coins. In such cases the same telephone line will be used in connection with both an ordinary subscriber's station and a coinbox station, (n this case the administrative difficulties are so great that it will normally be desirable to block the telephone from calls to operators' stations when the station is set for the coinbox funefion.

The solution to these problems has so far been to provide a digit analyzer in the coinbox. This analyzer checks the number selected by the person calling, and if the number is found to correspond to an operators' station, either a forcible release is caused to take place in the case of a rented coinbox, or the coinbox station is brought in condition for co-operating in the manual establishment of a call.

This solution is unsuitable if the operators' stations have a plurality of different numbers, or if different types of dials or keyboards are used. it is the object of the invention to provide an improved solution to the above mentioned problems. According to the invention, the operators' stations for manually established calls are equipped with a generator which upon switching-on of the telephone set of the operators' station transmits a coded signal of short duration consisting of one or more frequencies in the audio frequency range, and in coinbox stations from which manually established calls are admissible equipment is provided which in response to reception of the said coded signal makes the coinbox station ready for co-operation in the establishment of ibe call, while no such equipment is provided in coinbox stations -243719 from which manually established calls are non-admissible. In a preferred embodiment the advantage is obtained that only very ' simple equipment is required both in the central exchange and in the coinbox stations, because the coinbox station is arranged to transmit an identification tone for a limited period of time so that the operator is alerted to the fact that payment for the call is to be demanded, and the coinbox station transmits tone signals for identification of coins collected, while the value of these is not registered in the balance register.

In an advantageous embodiment of the invention coinbox stations from which manually established calls are non-admissible comprise equipment which in response to reception of the coded signal produces forcible release.

To reduce the risk of error, the coinbox station may comprise a receiver for the coded signal which is so arranged that upon identification of a first part of the coded signal it blocks the microphone while the remaining part of the coded signal is being received. Hereby the advantage is obtained that the last part of the coded signal is received without disturbance.

The invention will now be described in further detail solely by way of example, with reference to the accompanying drawings, in which:Figure 1 is a diagram of the equipment at an operators' station; Figure 2 is a diagram of the equipment in a coinbox station from which manually established calls are admissible, and Figure 3 is a diagram of a coinbox station, from which manually established calls are non-admissible.

In Figure 1, N is a key, by means of which the operator at an operators* station switches on the telephone set in usual manner. At the operators' position a coded signal generator 2 is provided,which is switched on simultaneously with the telephone set and emits a coded signal which is transferred to the line by means of a transistor Ql. During this transmission the connection to the telephone set is interrupted by means of a transistor Q2.

The coinbox station illustrated in Figure 2 comprises as usual a forcible release circuit 3,a coin control 4,a talking circuit 5 and a dial 6. in the coinbox station there is further provided a receiver 7 comprising a filter and decoder and arranged for receiving the coded signal from the operators' station. Moreover, an identification generator 8 is provided which is started by the coded signal, and this signal is also received by the coin control circuit which thereafter delivers coin signals for the collection of coins. - 3 42719 The identification generator emits for a limited period of time an identification tone so that the operator is advertised that payment for the call is fo be demanded.

As previously mentioned, the decoder may be so arranged that upon receipt of the first half of the signal from the exchange if blocks the microphone so that the second part is received without disturbance.

In the coinbox station illustrated in figure 3, from which manually established calls are non-admissible, a filter and o decoder are likewise provided to supply a signal when the coded signal from the operators' station is received. However, no identification generator is provided in this station and consequently no identification tone is sent back lo the central exchange. However, the signal from the decoder is received by the forcible release circuit which interrupts the connection. The forcible release clrcuitwill normally receive a signal for break down from the coin control circuit when the conversation time paid for has been consumed.Thus, in the system according to the invention the forcible release circuit has an additional function, viz. that of causing break down in response to the coded signal from th’e operators' position.

Also in this case the decoder can be so arranged that upon identification of the first half of the signal from the exchange if blocks the microphone so that the second half is received without disturbance.

Since the coded signal from the operators' position is intended fo be transmitted in connection with all calls to operators' positions, the system can also be used in connection with other subscribers' stations, if it is desired to prevent or register such calls.

Claims (4)

1. , Signalling system for manually establishing calls from coinbox stations, characterized in that the operators stations for manually established calls are equipped with a generator which upon switching-on of lhe telephone set of the operators' station transmits a coded signal of short duration consisting of one or more frequencies in the 5 audio frequency range, and that in coinbox stations from which manually established calls are admissible equipment is provided which in response io reception of the said coded signal makes the coinbox station ready for co-operation in the establishment of a call, while no such equipment is provided in coinbox stations from which manually established calls are non-admissible. 10

2. Signalling system according to claim 1, wherein in coinbox stations from which manually established calls are non-admissible equipment is provided which in response to reception of the coded signal produces forcible release.

3. Signalling system according to claim 1 or 2, wherein the coinbox station comprises a receiver for the coded signal which is so arranged that upon idenfi15 fication of a first part of the coded signal it blocks the microphone while the remaining ’ ’ part of the coded signal is being received.

4. Signalling systan substantially as described hereinbefore with reference to the accompanying drawings