UC15 detect one sim card but another no

Hi friends, I have a UC15 module, It works fine with one sim card but not with another. The sim card that is working is new but the problematic sim card is old, the problematic sim card works fine into a phone, could be a voltage problem with older sim cards?

the error:
+CME ERROR: SIM not inserted

Best regards,


Hello, the reason for returning this is that the SIM card was not identified, so I guess it may be:

  1. Poor physical contact.

  2. The UC15 Module does not support the old card, so you need to provide sim card information