Process for feeding audible tones into conference communications.

p0001The invention relates to a method for feeding audio tones in conference connections in a PCM time division switching system in the course of PCM words supplied by the conference participants and cached in a half of a conference memory, optionally converted into linear code representation total sum code words are formed, from which each several different partial sum code words are formed by subtracting one of said PCM words by caching in this half of the conference memory from there respectively, where appropriate, be sent to that conference participants after conversion back into non-linear code representation, whose total sum share they do not contain, while in the other half the conference memory new certificate from the conference PCM words are latched and the two halves of the conference memory alternately exchange their role.

p0002For PCM time division switching systems, it is known to generate audible tones using certain PCM words, which are sent periodically and the special sound-space programs, and then to a receiver side digital to analog conversion result in each case a specific audible tone ( see, eg, DE-OS 25 41 295),.

p0003In conference calls corresponds to the supply of such digitally generated audible tones of the intrusion of another conference participant. Accordingly, so far such audible tones were also all participants of the conference sent connection simultaneously. For specific call progress tones, namely, for example, for the cut-in or the call waiting tone, but it is also interesting to note that these are sent only to certain of the respective conference participants.

p0004Aufgabe.der present invention is therefore to provide a method for feeding audio tones in conference calls, which allows the Hörtoneinspeisung to selectively perform general and individual subscriber.

p0005This object is achieved according to the invention with the aforementioned kind materialize accommodated conference calls in that apart from the abovementioned total sum code words Hörtonsummencodeworte be formed, in addition to the PCM words supplied by the conference participants include the sum of play each one a specific audible tone corresponding PCM word, and that belong together total sum code words and Hörtonsummencodeworte be temporarily stored in a further buffer memory, is subjected to from which due to Hörtonsendekriterien jeweis specific same the partial summation.

p0006The inventive method can be carried out with a conference record that is changed only marginally over known conference records in construction and operation.

p0007The invention will be explained by way of example with reference to the drawing which shows a block diagram of a composition suitable for performing the inventive method conference record.

p0008In the present embodiment, it is assumed that the conference set shown in the figure of the Kop is pelgruppe a PCM switching center assigned to the 32 PCM lines are connected. Transferred to this PCM lines PCM words come after a series-parallel conversion and channel-wise interleaving on an eight line branches for the parallel transmission of the eight bits of the PCM-word time division line on which there is a bit transfer rate of eight Mbit / sec , In the figure on the left side of the incoming part Muxa and shown on the right side of the outgoing part Muxg this time multiplex line. occurring on this time-division multiplex line PCM-words belonging to normal two compounds, are mediated through a not shown time switching stage of the switching centers. Belonging to conference calls PCM words are however coupled to the illustrated conference record and pass via an input register Reg 1 or Reg2 to one or the other half RAM1 or RAM2 a conference memory. This conference memory halves are each divided into here 64 storage areas that are assigned the same 64 possible conference calls, and each have eight memory slots for eight conferees. In addition, this conference memory halves each have space for the case in the present three PCM words which serve to generate three different audio tones.

p0009The Conference storage parts RAM1 and RAM2 are driven optionally both during writing and during reading and change, as will be seen, alternatively their role, for example in receiving PCM words from the incoming multiplex line Muxa.

p0010During a pulse frame, in the example, the conference memory half RAM1 of information recording is used, enter the incoming on the time-division multiplex line Muxa PCM words representing the shares of each conference participant, in the associated memory locations of the memory areas of the Save IFTE. In addition to the time-division multiplex line Muxa incoming serving for representation of the audible tones PCM Wörcer that have been generated at a central location of a Hörtongenerator, enrolled in the designated storage spaces of the conference memory RAM1 half.

p0011In the subsequent pulse frame is carried by the conference memory half of the processing the goods so arranged PCM words, while the now incoming PCM words corresponding to the manner described above in the second half of the conference RAM2 memory eingeschrieben.-be.

p0012In the course of the mentioned processing, the Konierenzanteile representing PCM words are first read successively from the storage half RAM1 and, provided they have a non-linear code representation, subjected by means LIN a code conversion into linear code representation, to get in this form to an adder ADD. In this adder are the actual arithmetic unit ALU originating from the individual conference participants a conference call PCM words summed up in succession, the resulting subtotals respectively in the intermediate register AREG cached and then the arithmetic unit ALU are zugefübrt.

p0013The case generated total sum codeword GS is written on an intermediate register Reg 4 in another conference memory RAM 3 of the conference record, the handover but takes place such that this code word remains in the register AREG of the adder ADD.

p0014Now, the components used to display the progress tones PCM words from are from the memory RAM1 half successively read, optionally linearized, and to form separate jefeils Hörtonsummencodeworten to Gesai sum code words GS added. The individual Hörtonsummencodeworte be enrolled also after their creation in an individually assigned memory of another conference memory RAM 3, the n accordingly in n provided audible tones + 1 Speiclaerplätze, counter so four memory locations which. In this Konfe-Feazspeicher So are jetzt.außer the only thing the conference shares a conference call educated total sum codeword GS three Hörsummencodeworte HS1 to HS3, which are formed from the total sum code word and each Hörtoncodewort as the sum of play.

p0015In the course of the next processing step, which is also in the second noticed pulse frame, will be successively subtracted from any of the data stored in the memory RAM 3 Conference sum codewords one that derived from the conferees concerned PCM word. The decision on whether the subtraction is done from the total sum codeword GS or of any of Hörtonsummencodeworte HS1 to HS3, depends on whether a call progress tone to be displayed at this time, and if this is the case, which of the available audible tones the relevant Conference participants, which is associated with the timing just treated, is to be sent.

p0016The aforementioned subtraction is also carried out with the aid of the adder ADD.

p0017The subtraction results are optionally written into the individual conferees memory cells associated with the conference memory RAM1 part after conversion to non-linear code representation using the device KOM again. carried from there during the individual conference participants assigned time slots, an output from this conference storage part or an infiltration on the outgoing part Muxg the time division line. The individual conferees subtotals are supplied therefore each that are either composed only of the conference units is the other conference parties or from these Konferenzanteilen.und a generation of a specific audible tone serving PCM word.

p0018PCM words that arrive in the pulse frame the conference record in which effected the expenditure mentioned in the outgoing line of the time division multiplex line are rewritten after interim changing the operating mode of the conference memory halves in the conference memory half RAM1. The above mentioned processing of such PCM words in the form of a summation and subsequent subtraction is now carried out by the other conference memory RAM2 half.