D4 "RDY" (Green) is on
D8 "IN1" (Red) is off most of the time; it blinks on every now and then.D9 "OUT1" (Red) if on most of the time; it blinks off every now and then.D10 "ERR1" (Red) if off most of the time; it blinks on every now and then.
I don't know which LEDs you're referring to as BUSY1 and BUSY2. Those words do not appear on the PCBs and they're not mentioned in the "CBus to KNX Translator" manual.
D10 is ERR.
Photo of PCBs is attached.
I don't know what "NX screen" means. In the I/O monitor of the CBus Translator I can see that data is being sent to KNX but nothing is coming back:
Please check the KNX bus wires are screwed frmamly and has god contact. It apears that the data is sent to KNX but the module cannot detect any repy from the bus, hence the BUSY2 led is on
If the connection is good, the cbus to knx module or the KNX submdoule may be faulty