Hi Eitan, It looks to me like IB_RMPP_NO_RESP_TIME in ib_types.h is trying to mask off the RRespTime (high 5 bits) of RMPPFlags byte so it should be #define IB_RMPP_NO_RESP_TIME 0x07 rather than #define IB_RMPP_NO_RESP_TIME 0x1F As this does not appear to be used, this is merely cosmetic right now. -- Hal