@skyfree same issue here.. TL-MR6400 No SIM card detected. Please make sure that your SIM card is slid properly in the card slot. The sim is in the slot and used to work last week. Then its started...

@vitosky since nobody bothered to reply I will in case the next person wants answers: you would think it uses cable and if no connection switches to sim data but no.. IF you want to use cable and...