Reading the card and the .DDD from your phone (OTG)
With a USB OTG cable (or over Bluetooth with a compatible reader), your phone becomes your download terminal: plug in, pull the card and you can open the tachograph file right there. The app decodes the .DDD file on the spot, so you see the hours you've got left before a border and don't pick up a fine for stacked-up driving.
If it's your first time, the step-by-step for cable, permissions and reading is in the mobile card reader (OTG manual), and the full app install is in your tachograph on your phone.
So nothing goes missing: a copy in the cloud
Every download you make from the app saves itself into your legal custody storage, so the transport manager gets the drivers' data on the road without waiting for them back at base. How that secure, encrypted copy works, without depending on you remembering, is in secure cloud sync and archiving.
And since those records are the same ones that feed the allowance and overnight calculation, the books come out straight and evidenced, ready for a DVSA or HMRC check.
Warnings before you go over: rest breaks in the cab
The app carries a cab version of the rest dashboard: it warns you about the 45-minute break and the daily driving limits (9h, or 10h twice a week) before you go over them, not after. No more keeping the tally on paper and hoping for the best.
You've also got the rest of the tools for the driver to hand from there, built to sort out technical questions without climbing out of the cab.