Android: getDeviceId () returns IMEI, adb shell dumpsys iphonesubinfo returns device identifier = NULL

Question

Different results for my inexpensive Chinese tablet. This is not a phone, so why getDeviceId () returns a number that seems like a valid IMEI?

C:\>adb shell dumpsys iphonesubinfo
Phone Subscriber Info:
  Phone Type = GSM
  Device ID = null

but using

TelephonyManager tManager = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
String uid = tManager.getDeviceId();

uid = 35881700 ... (I do not show the entire IMEI number for privacy)

Answer 1

Does your tablet have any GSM radio? (Sorry to send a response, but I am not allowed to leave comments ..)

According to GSMPhone.java in the Android version I'm looking at, IMEI is installed when the radio used by the device is initialized.