Establishing telecommunications call paths between clustered switching entities

The present invention relates to converting pulse code demodulation (PCM) signal current into Asynchronous Transfer Mode (ATM) cells to switch and transmit over a telecommunications network. Each cell carries a PCM sample of up to 48 different voice connections, voice connections are chosen from PCM data streams because they have a common destination. Cells are transmitted on ATM virtual circuits, each circuit transmits one cell every 125 µs. Advantageously, ATM transmission systems interconnect with PCM systems without contributing appreciable delay and without requiring additional buffer memory. Advantageously, new paths or voice paths can be established most of the time, using available slots in existing virtual path cells.