A telecommunication system and a method for matching the numbering schemes of two telecommunication systems.

The invention relates to a telecommunication system and a method for matching the numbering schemes of telecommunication systems. The telecommunication system comprises a transmission network comprising at least one mobile exchange (MSC1, MSC2) associated with a subsystem (BUC, BU1-BU6), the calls of subscribers (MT1-MT6) in the subsystem being routed through the transmission network and the mobile exchange. A numbering scheme of the subsystem comprises an X-bit binary subscriber identity code (PID) and a numbering scheme of the transmission network comprises a Y-decimal subscriber identity code (MSIN). In the transmission network the subscriber (MT1-MT6) of the subsystem is assigned a Y-decimal identity code comprising a decimal number derived from the X-bit binary identity code of the subscriber and having no more than Y-1 decimals. At least one system identification decimal is introduced into the obtained decimal number at a predetermined position to indicate that the identity code belongs to the subscriber (MT1-MT6) of the subsystem.