In an embodiment, a method comprises: sending a message from a master unit of a distributed antenna system to a remote unit of the distributed antenna system, wherein the message includes a list of service frequencies and applied standards for a base station; sending a downlink signal generated based on a base station signal from the master unit to the remote unit; decoding the downlink signal based on the list of service frequencies and applied standards for the base station; extracting a base station clock signal from the decoded downlink signal; and synchronizing an internal clock of the remote unit to the base station clock using the extracted base station clock signal.