Difference between the BT3554 and 3554. (Contact check)

Difference between the BT3554 and 3554. (Contact check)

Question

Is there any difference regarding contact check between the BT3554 and 3554?

Answer

The frequency and amplitude used for contact check are:
  3554:  2kHz, 100uA
  BT3554:  11.76kHz, 200uA

The contact check signal is applied even if the disconnection detection function is OFF.