A slow fast programming method for efficient remote field update in distributed base stations overcomes significant fiber propagation delay associated with a remote unit by applying programming data at two clock frequencies. A fast clock frequency is used for programming data phases that do not require a response from the remote unit, and a slow clock frequency is used for programming data phases that require a response from the remote unit. Testing a base unit and a remote unit is also accomplished with more than one clock based on the test dependence on a remote response.