When using virtual serial port (VSP) functionality, how can I detect whether the module is in Bridge Mode versus Command VSP Mode?

Answer

If the configuration key 100 is left at its default value (that is in factory default state), it is in Command Mode or Bridge Mode based on the state of the input nAutorun pin. Simply monitor the BL600’s nAutorun pin (40). If nAutorun is low (0V), it is in Command Mode and if high (Vcc) it is in Bridge Mode.

If the configuration key 100 has been modified, then you have forced it into one state or the other. In other words, you have triggered it through an action which you are aware of.