DE721907C - Circuit arrangement for telecommunications systems with call forwarding, especially telephone systems - Google Patents

Description

Circuit arrangement for telecommunications systems with call forwarding, in particular Telephone systems The invention relates to a circuit arrangement for telephone systems with call forwarding to. a representative of a called connection point and switching back the call to the first called connection point in the event of no reply of the deputy, in particular telephone systems.

Arrangements are already known in which a call forwarding called deputy of your main office at any time after picking up the phone. of Handset and pressing an exchange key to the calling, but not yet queried exchange line can turn on. In these orders, the representative of a main office called by lifting the handset first connected to the house connection path, and it is then after it has been determined that there is no call on the house line, press the exchange key Press and thereby connect to the calling outside line. It requires so this well-known. Arrangement a cumbersome operation for the representative the main office called.

But there are still systems known in which with call forwarding to a representative of a called connection point the connection of the representative to the calling trunk line or initiated. Get in touch in these known systems of .Vertreter during the call forwarding by picking up of Handset, so is or will be. The representative alone with picking up the handset with the calling Trunk connected. However, with these systems, the call to the representative the connection of the representative or the preparation of the connection is terminated of the representative canceled. The representative who picked up the call and answers by picking up the handset, under no circumstances can a connection be established with the calling trunk.

The invention aims to address the disadvantages of the known arrangements avoid and achieve this by having switching devices at the switching point die «b, ei call forwarding to the deputy whose automatic connection Prepare the calling line so that the deputy can answer of the call only needs to pick up his receiver and that this preparation too after switching the call back to the first called subscriber remains as long as the call continues.

The arrangement according to the invention enables the deputy, once a call has been forwarded to it, at any time for as long as the call is at all, the calling trunk is reached by lifting the handset. Advantageously, if the station called first does not answer, control effectively switching means in the first call forwarding to the deputy a die Connection of the representative preparatory auxiliary relay, which is independent from call forwarding or call switching back to the termination of the call in holds its own circuit. The auxiliary relay prepares in connection with a relay controlled by the ringing current, the circuit of one of the representative office assigned connection relay, which is then sent to the representative office when the loop closes initiates the connection to the calling exchange line. To that controlled by the Rufstrom To keep the relay switched on safely even during the pauses in the i o-S: ek. Call, is an electrolytic capacitor that is charged while calling and discharges during the pauses in the call via a second winding of the relay and this keeps excited.

The accompanying drawing shows a private branch exchange in which a main station HSt and several extensions are located on an exchange line AL , of which only the external @ extension ANI is shown. In the drawing, only the details necessary for understanding the present invention are shown in more detail of these subscriber stations. The switching processes are as follows. When a call comes in from the exchange, the relay AR in the main unit is excited by the alternating ringing current through the capacitor C.3; it switches on relay B via its contact i ar. At the same time, in parallel with relay B, the alarm clock for the main unit is activated. While the relays AR and B are periodically switched on and off by the IO second call, the relay F, which was activated via the contact for 2 hours when relay B was initially triggered, remains during the entire duration of the call, i.e. also during the pauses in the call. in the work situation. When the contact 3 b is opened, the capacitor EC, which can be designed as an electrolytic capacitor, for example, discharges via the winding II of the relay F, so that this winding, since the capacitor EC is selected to be sufficiently large, during pauses in the paging of the capacitor discharge current flowed through and therefore kept excited. A circuit for the thermal relay Th is therefore established via the contact 4. f and the contact 5 z.

If the main unit does not answer within a certain time, e.g. B. from three calls, the thermal relay Thl is activated and switches on the relay Z via its contact G tlal. This forms a hold circuit independent of the ThermDrelais Tltl via contact 7 f and its own contact 8 z. Furthermore, the heating circuit of the thermal relay Tlai is interrupted by switching the contact 5 z and a circuit for the call relay R is prepared for it. The relay R is switched on periodically depending on the relay B (in the rhythm of the Rufw: echselstromes) and causes the transmission of ringer current from the Rufwe @chs-elstromquelle of the private branch exchange to the subscriber of the external extension ANI via the contacts ior and ii Y. The alarm clock Wlt of the main office can be switched off via contact 24 z while the call is being forwarded to the deputy; Furthermore, a circuit for the relay T is formed via contact 1 3 z, and the already closed contact 12 f. The relay T responds and remains independent of the contact 13 z via its contact 1 a t until the call is terminated. The activation of the subscriber of the external extension ANI is prepared by the response of the relay T.

If the subscriber of the external extension AN reports by picking up his receiver, he will, without him as usual with issuing exchange connections z. B. his earthing button ET must press, automatically switched to the incoming exchange line just by picking up the handset. When the receiver is picked up, the relay A responds and switches on the relay V1 via its contact 1 5 a, which closes a circuit for the through-switch relay H with its contact 16 v1. The line HL leading to the house control center (line selector or the like) is switched off via contacts 1 8 1z ünd 1 9 h, and the exchange line to the subscriber of the external extension ANl is switched off via contacts 2o h and 2111, with the main unit HSt being switched off.

If the subscriber of the external extension does not answer within the call forwarding time, the call is switched back to the main unit. - The switched on via the contact 23 z thermal relay Th2, which z. B. becomes effective after three more calls, the relay Z short-circuits via its contact 25 th2, so that it drops out. The drop in relay Z causes (via contact 5 z) the switch-off of the extension call relay, R and thus the termination of the call to the external extension. However, the relay T, which prepares the connection of the external telephone station, remains energized. Furthermore, the alarm clock ft of the main unit is switched on again via contact 24z, while the heating circuit of the thermal relay Th 2 is interrupted by opening contact 23 z; for this, the thermal relay Thler is switched on again via contact 5 z.

If now, after switching back the call to the main parts, the external extension reports, the arrangement according to the invention provides the possibility that the subscriber of the external extension can also connect directly to the incoming exchange line at this point in time; because the relay T which prepares the excitation circuit of the connection relay H is also excited during the switching back of the call to the main station. If, therefore, the participant now lifts: the external fog control picks up his receiver, the relays A and V1 respond in the manner already described and close the circuit of the connection relay H via the contacts 7 7 t and 1 6 v1.

However, the main unit responds before the external unit has switched on to take the call, it is not known here shown in more detail the Aasschaltung the subscriber of the external extension to the trunk line, e.g. B. by switching off the relay H, prevented.

Claims (5)

PATENT CLAIMS: i. Circuit arrangement for telecommunication systems with call forwarding to a deputy not directly on the calling line when a called subscriber does not report and the call is switched back to the first called subscriber when the deputy does not report, in particular for Fernspr. Mechanlaggen, characterized in that switching devices (F, T ), which in the case of call forwarding to the representative (AN,) prepare its automatic connection to the calling line (AL) so far that the representative only needs to pick up his - handset to receive the call and that this preparation also after switching the call back to the first called Subscriber (HSt) is maintained (via contact iq.t) as long as the call lasts. 2. Circuit arrangement according to claim i, characterized in that in the event of failure: the first called subscriber (NSt) becomes effective switching means (F, Z) when the call is first redirected to the representative (AN,) an auxiliary relay (T ), which now remains in its own circuit (via contact 1q. t) regardless of call forwarding or call resetting until the call is terminated. 3. A circuit arrangement according to claim 2, characterized in that the auxiliary relay (T) which takes effect when the call is forwarded, in conjunction with a relay (F) controlled by the Rufström, prepares the circuit of a connection relay (H) assigned to the proxy, which when the loop closes at the proxy Call switching to the calling exchange line (AL) initiated. q .. Circuit arrangement according to Claim 3, characterized in that that the relay (F) controlled by the ringing current (via relays AR and B) on first arrival of the ringing current is excited and in the pauses during a call over holds a winding (II) excited by capacitor currents. 5. Circuit arrangement according to Claim q., Characterized in that a capacitor charged during ringing (EC) during the pauses in the call via the holding winding (II) of the controlled by the call current Relay (F) discharges.