CH652881A5 - Method for exchanging switching signals in the connection traffic in telephone networks - Google Patents

Description

The invention relates to a method for exchanging switching indicators in connection traffic in telephone networks using pulse indicators, wherein after sending an occupancy indicator by a first

A second system sends out a polling code and after this polling code has been sent, a first group of audio frequency codes is sent out as an identifier and then a second group of audio frequency codes is used as a dialing code by the first system and continues to follow the dialing code for the information. Intercom-free »or« Intercom-busy »certain different indicators are provided.

An aforementioned telephone extension network with, for example, a main system HA and one or more dialing documents UA is known from the German patent DE-PS 25 32 927. The use of bidirectional connection lines in connection traffic, in particular in telephone networks, is known as such. If this involves connection traffic between remote telecommunication private branch exchanges and if the private branch exchanges are equivalent, this is generally referred to as cross-connection traffic. If, on the other hand, there is telephone traffic between a main system and a so-called dialing subsystem, from which connections to the public office can only be established via the main system, the term is generally used to refer to secondary lines and dialing subsystem traffic. In the present method, it is a question of alternating current indicators and audio frequency indicators to be transmitted in addition to the dialing indicators, wherein the audio frequency indicators can also be multi-frequency indicators. The AC indicators are referred to as the main identifier and the audio frequency identifier (multifrequency identifier) as the secondary identifier. This use of main license plates and secondary license plates for the transmission of license plates via sealed connecting lines is already known from the German published application DE-OS 2 233 764.

To expand the features of a telephone private branch exchange in accordance with the known method according to German Patent 25 32 927, the object of the method according to the invention should be that, in the case of an extension network with the known identification system, the initiation of a callback from a call station of a private branch exchange of the system network to a call station of another Private branch exchange of the system network is possible in a simple manner.

This is achieved according to the method according to the invention in that after the identification of a "station-occupied" identifier in the first system, a code sequence storing a callback request and triggering the later callback from the second system is transmitted from the calling station and that for a callback in the second system, the address of the calling station of the first system contained in the identifier is stored.

This has the advantage that it is possible to store a callback request from a call station of a first private branch exchange belonging to a private branch exchange in a second private branch exchange belonging to the private branch exchange with the existing identification system in a simple manner.

The method according to the invention is explained, for example, using two figures.

FIG. 1 shows the sequence of establishing a connection from a main system HA to a dialing subsystem UA in relation to the occupancy indicator, polling code, identifier, dialing indicator and “intercom-free” or. "Station busy indicator" and the indicator for entering the callback request.

Figure 2 shows the characteristic course of the s

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Call back to the originally calling station.

It is assumed that the known identification system is to be used to set up a connection between a call station of a main system HA and a call station of a dialing subsystem UA belonging to the extension network. The main system HA first sends out an occupancy indicator HK1, the latter representing a main identifier consisting of an alternating current identifier. Sending out the occupancy indicator on the receiving side - the dialing subsystem UA - causes the provision and switching on of dialing reception devices and the dialing subsystem sends a polling code HK2 as the main identifier to the main system HA after the activation of these dialing reception devices. After receiving this polling code HK2, the main system sends out an identifier consisting of the secondary codes NK1 to NKn, which contains, among other things, information about the calling subscriber station (address) and the corresponding private branch exchange. After receiving a flag MZ (audio frequency multiple indicator) transmitted by the main system, the further audio frequency multiple indicators WK1 to WKn arriving from the main system are evaluated by the dialing subsystem as dialing signals.

After receipt of the complete dialing, a free-busy check is carried out on the receiving side (UA), the main codes HK3 and HK4 being sent to the main system when the telephone extension is free. After lifting the handset at the called station in the dialing subsystem, there is a normal telephone connection via the main system and the dialing subsystem.

If the desired extension was busy in the dialing subsystem, the main codes HK5, HK6 and HK7 are sent to the main system as appropriate information. The subscriber calling from there receives a busy tone.

If the extension subscriber of the main system HA wants the subscriber to call back in the dialing subsystem, he can, after the busy tone has arrived, for example by post-dialing, that another main identifier HK8 is sent from the main system HA to the dialing subsystem UA, which is a the secondary identifier NKS containing the information "callback" is assigned. The dialing subsystem recognizes from this that a callback is requested from the subscriber of the main system, and it takes the address of the subscriber who wishes the callback from the present identifier (NK1 to NKn), and at the same time the address of the call station remains saved by the from the recall. In the following, the call station of the main system from which the call was originally made is called call station 1 and the call station in the dialing subsystem from which the callback is to be made is called call station 2.

The dialing subsystem checks after a recall has been made

652 881

on station 2 until it becomes free. After the call station 2 is cleared, the main system HA is automatically assigned with the help of an occupancy indicator HK9 (Figure 2, AC power indicator), which means that after making and switching on dialing reception devices in the main system, a polling indicator HK10 (AC power indicator) is sent from there. Upon receipt of the polling code, the dialing subsystem sends out a tone frequency code string. This tone frequency identifier string initially consists of the tone frequency identifier NKS, which now indicates to the main system that an incoming connection request is present, which is based on an original "call back". The subsequent tone frequency identifiers NKn + 1 to NKn + x mean the identifier of the call station 2 and are used for evaluation by the main system. This is followed by a flag MZ 'as a tone frequency indicator, which means that the tone frequency indicators WKn + 1 to WKn + x which now follow are to be evaluated as dialing characters by the main system.

Assuming that the call station 1 of the main system is free, the main codes HK11 and HK12 (AC code) are sent from the main system to the dialing subsystem. There is a ringing tone on station 1. If the subscriber picks up there, he receives a ringing tone while there are 2 ringing tones at the subscriber station.

If one assumes that the call station 1 in the main system is occupied by another call, then the main station HKir and HK12 'identifying the call station 1 as free identifiers are sent from the main system to the dialing sub-system, with a call waiting or a call in the main system The call on station 1 is connected to the existing call. After lifting the handset at station 2, the speech connection is switched through.

If it is assumed that after the recognition of "call station-free" at call station 1 and the ring tone there, the call is not picked up (lift the handset), then after a timer has elapsed, the ring tone at call station 1 is deactivated and the callback is identified deleted in the dialing subsystem.

If, on the other hand, after recognizing «Intercom 1 free», the intercom 2 in the dialing system is marked as busy (since another call has arrived and has been received), the callback attempt is interrupted and an attempt is made again after a timer has expired.

The same also happens if there is no free extension line when trying to set up the callback connection from the dialing system to the main system. It is then also repeatedly checked for a free branch line and after occupying such a free branch line, the assignment of an input of the main system takes place in the manner described above.

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Claims (7)

652 881 1. A method for exchanging switching indicators in connection traffic in telephone networks using pulse indicators, wherein after sending out an occupancy indicator by a first system, a second system sends out a polling code and after sending out this polling code, the transmission of a first group of audio frequency codes as an identifier and thereafter a second group of tone frequency signs as a dialing code is carried out by the first system and, in addition to the dialing codes, certain different codes are provided for the information “intercom-free” or “intercom-occupied”, characterized in that after recognition of the “intercom” - busy »declaring license plate (HK5, HK6, HK7) in the first system (HA), from the calling station sending a code that stores a callback request and triggers the later callback from the second system (HK8, HKS) t and that for a call back in the second system (UA) the address contained in the identifier (NK1 to NKn) of the calling station of the first system (HA) is stored. 2. The method according to claim 1, characterized in that in the event of a callback attempt on the part of the second system (UA) and no free auxiliary line between the two systems (HA, UA), the callback attempt is repeated after a timer has expired. 2nd PATENT CLAIMS 3. The method according to claim 1, characterized in that in the event of a callback attempt on the part of the second system (UA) and "do not report" the originally calling station in the first system (HA) after a timer has expired on the part of the first system (HA) an identifier causing the cancellation of the recall is sent to the second system (UA). 4. The method according to claim 3, characterized in that the cancellation of the recall on the part of the second system (UA) after the absence of a "call station-free" or. “Call station busy” indicator is used. 5. The method according to claim 1, characterized in that in the event of a callback attempt on the part of the second system (UA), despite the "busy" status of the originally calling station in the first system (HA), the information "station-free" from the first system (HA) »Is sent to the second system and there is a call waiting or intrusion at the originally calling station. 6. The method according to claim 1 to 3, characterized in that with a free originally calling call station and free call station marked with callback, the second system (UA) sends a free tone to the originally calling call station and ringing tone to the call station marked with callback. 7. The method according to claims 1 and 6, characterized in that when the ringing station marked with the callback is sent before the ringtone is sent and after free identification, the busy line is sent to the first system (HA) by another conversation on the part of the second system (UA) and after the callback attempt is repeated at a certain time.