“If the config-pin is asserted low twice, it will not give prompt the second time. So if the module is already in config-mode after power-up sequence (if config-pin voltage raise slowly compared to VCC), then it must have a Reset low before
config can go low again and module will give new prompt. If you try Reset + config in a sequence from a controller (or manually), then you should see prompt ‘>’ for each config low.
It can also be a problem if the RXD pin is floating during your tests; Then the CMOS input might cause a lot of characters to be sent, and then I am not sure how config-mode will behave. So during all tests, use a maximum 8k2 ohm resistor as pull-up to
Your voltages are ok, the module should work fine.
The RTS/Sleep pin does not matter unless the module is configured for using this pin, but in the default mode it is not used
Last Update: October 5, 2017