Abstract: Method of exchanging information between Radio Remote Unit (RRU) and Baseband Unit (BBU) in Evolved Node B (eNodeB) when there is loss of synchronization of the Common Public Radio Interface (CPRI), including a) listening on BBU Small Frequency Factor (SFP) interface; b) when RRU detects an CPRI asynchronous event within a time period, conducting a hardware and software uncertainties test including the CPRI status, frequency, temperature, voltage, current and Radio Frequency (RF) operation; c) RRU converts checked uncertainty into text string; d) encoding text string into Morse code as binary bits 0,1; e) sending binary bits to the BBU by SFP module optical signal turning on and off; f) received data at the BBU SFP interface is encoded to Morse code, convert Morse code to text and writing file; and g) periodically checking the received text strings, collating them with predefined error codes, and take necessary trouble shooting steps.