Atm networks for narrow band communications

(57) It is changed into an Asynchronous Transfer Mode (ATM) cell, in order that a summary pulse code modulation (PCM) signal stream may cross an electrical communication network and may exchange and transmit. Each cell carries one PCM sample to a maximum of 48 different voice connection, and these voice connection is chosen from a PCM data stream by the reason they have a common address here. These cells are transmitted through the ATM virtual course in which each course transmits one cell every 125 microseconds. In the unit for these ATM signals being exchanged, without adding change to the contents of those payloads in the unit for exchanging cells (cell exchange), and exchanging the signal over the voice connection of further each, Exchange between the cells of an ATM signal is performed (celery mapping). This ATM transmission system interfaces as a strong point, without without it is accompanied by the delay which can recognize an addition to be a PCM system, and needing additional buffering. As a strong point, a new voice course can be set up in almost all time using the vacant slot in the cell of an existing virtual course. As a strong point, a big electrical communication network is realizable using a small number of unit replacement. Although the celery mapping stage by which interconnection is carried out as a strong point in one or more cell exchange stages offers the pliability for carrying out interconnection of the big access switch, this celery mapping stage can also be made into the part of an access switch here. As a strong point, an access switch includes cell mapping or the distribution stage with the function which assembles the cell which consists of the PCM sample turned to the common output of an access switch. In this way, / in a cell switch next the assembled cell, It is exchanged in the celery map unit for bringing together the PCM sample turned to the common address in each cell of an ATM output stream, and as this result by a transit network, In order to carry out a ディス tribute to other access switches of a big network, an exchangeable output signal is acquired simply and efficiently. As a strong point, this celery map unit offers the element used as the key for realizing an efficient and large-scale ATM voice network. In order to use it with a PCM switch, it is required to offer PCM data and the accompanying supervisory signal. As a strong point, with this composition, it is possible to pass a supervisory signal within an access switch, for this reason a compatible function with an existing exchange system becomes simple.