A radio base station (20) has an internal interface (26) connecting a radio equipment (RE) (24) and a radio equipment controller (REC) (22). The radio base station performs a pre-start-up procedure or method for the internal (26). The pre-start-up procedure is performed preparatory to and/or in conjunction with a start-up procedure for the internal interface. As on e of its aspects, the pre-start-up procedure involves storing one or more previously proven combinations of line bit rate and protocol as stored combination(s) for use on the internal interface. Prior to synchronization of the internal interface, the stored combination(s) are retrieved and included in a temporary available set of combinations of line bit rate and protocol. Thereafter the start-up procedure for the internal interface is initiated for the purpose of determining efficacy of the temporary available set. Should synchronization of the physical layer by the start-up procedure succeed, the pre-start-up procedure uses a valid combination of line bit rate and protocol in the available set for negotiating between the radio equipment controller (REC) and the radio equipment (RE). Should the start-up procedure fail, the pre-start-up procedure removes a failed combination of line bit rate and protocol from the set.