Possible to use 4 wire cable to 3DR Radio V2?

I’m upgrading my telemetry unit, but now realise that the 3DR V2 radio does not communicate without the CTS / RTS wires, like the old unit used to do. Is it possible to disable this feature on the radio so I can use my existing cabling? I’ve made sure RTS CTS is checked off on both sides, but the modems still only talk if there’s flow control wires.

Thanks

After fiddling a bit and switching units around, I just left it on for a while and suddenly it started communicating. I read somewhere the internal buffer will fill up, after which point the sending unit will send info regardless.