Comment by mrjeeves

Hello, article editor here. Many Android devices with Qualcomm chips offer the option to expose a modem diagnostics port over USB meaning a rooted device isn't even needed. It's just much easier to use NSG rooted on-device than going around with a laptop places.

It's as simple as using Scat (https://github.com/fgsect/scat) with the modem diag port enabled to view all signalling traffic to/from the network.