Protocol State of the ML Active Variant. - sysStartUp - an Establish request arrived to the V5.1 interface. - waitForVarId - the variant and the Interface Id were requested during the system start-up procedure. - activatePstn - activation of the PSTN Data Link was requested during the system start-up procedure. - restart1 - the PSTN restart procedure is in process. - inService - the V5.1 interface is IN SERVICE. - restart2 - the V5.1 is in AN5 state (sends restart complete to all PSTN protocols and changes status to In-Service). - restart3 - the V5.1 is in AN6 state (sends restart complete to all PSTN protocols and changes status to In-Service). - waitV5Init - this state is entered when the system's management is in In-Service state, Switch to a new Variant is received and V5.1 interface will not be restarted. - switchOver - this state is entered when the system's management is in In-Service state, Switch to a new Variant is received and V5.1 interface will be restarted. - ctrlDataLinkRel1 - this state is entered when the system's management is in In-Service state and Release Indication is received. Timer TC1 is running in this state. - ctrlDataLinkRel2 - this state is entered on reception of Release-Indication in 'restart3' state. - outOfService - the V5.1 interface is Out-of-Service. - notDefined - V5.1 is not defined for this interface.