Abstract: Special services are switched to subscribers whose telephone sets are connectable to a time division multiplex (TDM) system. Each special service information unit is converted periodically into digital service words which are stored in a word memory and transferred from there during allotted time slots according to the time division multiplex system. A subscriber who calls one of the special services is allotted an idle time slot during which there is accessed an address associated with the called special service. The address activates the respective word memory for reading and transferring the stored special service information unit to the time division multiplex system. The same digital service word is read by means of the same address during different time slots as many times as there are subscribers who are switched to the associated special service.