There are 64 LCR class marks which can be used for controlling the dialing plan prioritization and for trunk group selection within a route.

All told, 32 LCR classes of service (LCOSV and LCOSD) can be created with the combination of the 64 class marks (LCOS). In addition to its conventional COS, every station, circuit and attendant console is also assigned an LCOSV/LCOSD setup with the AMO COSSU for the authorization test in the case of LCR. The LCOS's of the LCOSV/LCOSV are prioritized in the path selection when outgoing in the case of the AMO's LDPLN / LDAT IN. In the case of circuits whose signalisation behavior does not allow the transmission of the LCR class marks, the COT parameter OLCR / OLRD (signalisation procedure without LCR) must be set. In this case, the LCR class marks of the circuit (e.g. assigned with AMO TDCSU, parameter LCOSV) are used for all incoming calls.