It is in the CONC that the line cards are placed.
In order to route calls to different DLEs or DMSUs all traffic is quantanised (i.e analogue to digital converted speech placed in to Time Slots and built into Time Frames) which are placed on to the 2Mbit 30 channel PCM COAX highways and sent out from the Concentrator Units towards the Time Switches. In Ericsson AXE10 world this can be written as ETB to ETC via 2Mbit COAX using V5.2 and on to TSM/SPM.
Thereafter it is routed using the B-number analysis and placed onto the correct Routing Case depending on the destination of the call.
The above switch is one of the most robust switches I have ever experienced as it has been moved at least 6 times during its (to date) 30 years of service.