Look at the SERIN2/SEROUT2 commands in the manual.
They allow you to specify optional flow control pins which you would connect to the RTS/CTS pins of the module you're using if it has hdw flow...
PBP command SEROUT2 can handle flow control.
With that said I've never needed to use it with OpenLOG but it depends on how much data and at what speed you you're trying to log.
Re: Simplest way to write to USB stick or TF/SD card with PBP?
Thanks, I'm only going to write to flash drive, so I'll need SERIN for just status checking, whenever drive is physically present.
CuriousOne Yesterday, 16:10