Devices that still work when the internet doesn't.

Automotive / head unit

Sony XAV-AX4000

D1 Local Only — Speaks only to hardware you control.

The unplug test

Nothing about this head unit depends on the internet. It plays FM/AM radio and USB/Bluetooth audio with no phone connected at all. When you plug in an iPhone or Android phone (by USB or by pairing its own Wi-Fi/Bluetooth directly to the unit), you get Apple CarPlay or Android Auto — navigation, messaging and music are then supplied by apps running on the phone itself, not by Sony. Sony operates no cloud service this unit talks to and no Sony account exists to lose; unplugging the router at home has no effect on it because it was never connected to a home network in the first place.

Why this tier: The unit has Wi-Fi and Bluetooth radios (FCC grant AK8XAVAX4000, 2402-2480 MHz and 5745-5825 MHz), but Sony's own Help Guide shows both are used only to pair directly with the driver's own phone for wireless Apple CarPlay/Android Auto and Bluetooth audio/calling — the wireless-CarPlay pairing instructions have the owner turn on Wi-Fi and Bluetooth 'of your iPhone' and select the head unit's name on the phone's own settings screen, a device-to-device pairing with no Sony server named anywhere in the setup flow. No Sony account, app, or cloud service is referenced in the manual for any function of this unit. No vendor cloud exists for this device, so per the decision table this is D1, not D2.

Specifications

Account requirednone
Works offlinefully
Lost when offlineApple CarPlay / Android Auto features are supplied by the connected phone's own apps and connectivity, not by this unit, so they are unavailable without a phone present — this is phone dependency, not a Sony cloud dependency.
Forced firmware updatesunknown
Radioswifi, ble
FCC IDAK8XAVAX4000
Local controlunknown
Phones homeunknown
Parts availableunknown
Availabilityin stock
Price bandunknown
Vendor risk 0 / 3

Where to buy

Open questions

Sources

Class A is primary (manual, FCC filing, teardown). Class B is corroborated community reporting. Class C is never sufficient alone.

History

Last verified 2026-09-03 — 3 days ago.