Hi Pawel, As mentionned Sparky, CP1W-CIF41 does not support officially SEND/RECV/CMND commands. Even if it seems to works, we (I) do not have the detail of when It can work or not. But, I agree also with Sparky, using the NSJ to send/receive should works ! Do not forget to recycle the power of the CP1L with its CIF41 after writing a routing table and remind also that frame managed by the CIF41 should have a size less than 1024bytes. Hope this help. regards, JPV