| 摘要 |
PURPOSE:To form an exchange without vacancy of line capacity, by inserting voice data or the selected signal tone to a time slot assigned to a subscriber in accordance with information, in a time division type digital exchange. CONSTITUTION:When time slot Ti is assigned to subscriber SUB, tone transmission instructing information tno from signal tone generator TGO is read out by time slot Ti, and selecting circuit SEL selects tone data, and this data is written onto voice memory STM. The selected tone is read out by time slot Ti and is converted to an analogue signal by decoder DEC and is transmitted to subscriber SUB. If the signal tone is not transmitted, information not to transmit the signal tone is set as contents of signal tone transmission instructing information TB, and selecting circuit SEL is controlled by this information to select voice data from coder COD. Consequently, the signal tone is transmitted without assigning private time slots to respective signal tones. |
