I see RX, TX, 3.3V and ground pads on the circuit board of the map2nd.

Is this a serial port? Can I use this to talk to a serial device remotely?

Thanks!

If anything, this is TTL-level serial. You'd need something like MAX232 to convert levels to RS232 levels (which is 5V), without it you'd fry the board components.

Next problem is that this serial interface is not enabled in ROS on mAP ...

USB port is there ... can be used for flash or modem.
It has already been done.

RS232 levels (which is 5V)

±3-15. The -3 to +3V band is invalid.

TTL/UART is not RS232.

There are actually two different TTL's, a 3.3V and a 5 V one. (the former being sometimes called LVTTL)

Most (not all) circuits/boards that use 5V TTL work with 3.3V levels, while using 5V TTL levels on a 3.3V board may actually fry it (the distinction is between "pure 3.3V" and "5V tolerant").

https://documentation.euresys.com/Produ ... levels.htm
https://learn.sparkfun.com/tutorials/logic-levels/all

Only for the record there is even another two lower levels, 2.5V and 1.8V.

Converters that are multi-level do exist, example:
https://www.usangreencable.com/products ... le-adapter