@robski Actually there is a DB9 layer (see here) which is nice. I don't want to have to do soldering and have dangling wires and stuff.

But what about battery life? Do you know which core has best battery life?

Hi! I’m a newbie to IoT devices like this, but I need to build a small datalogger for some medical equipment. I am unsure which core is best for me. Here’s my requirements:

• Best possible battery life
• Must be compatible with the RS232 Module 13.2 with DB9 Male
• Must have an SD (or microSD) card slot

Based on these few requirements, can you suggest a core module? I think that a few of them will work, but I’m not sure which one has the best battery life?

Best, John