error503

No, that's not what it means. The phone knows its location because it can receive the GPS signals. There is no 'sending' involved at all, GPS is receive-only. To 'beacon' something it needs a transmit radio. Traditionally this is the cellular network, but it appears Apple has added a new satellite radio to their phones to augment this.

The obvious prevalent use case is adding a business / work line via your company's VoIP provider to your personal handset (or a company one, for that matter). I'm sure this is very common, and I have both done and supported it at multiple employers. Personally I have also in the past used VoIP accounts for cheap long distance, but I maintain a cellular service for reliability with local calls.

Having this functionality integrate with the OS is much handier than the clunkiness of dealing with individual apps, and this idea of replaceable parts is a key advantage of Android in general.

Emergency calls probably warrant special care and maybe more rigid handling, I will grant, but there's no reason not to support this in general.

Accurate delay compensation is necessary to enable redundancy. IF you need multiple GrandMasters at different locations in the facility, using independent RFoF systems and antennas, they will have different GNSS delays, and that difference will propagate down into uncertainty on the hosts. There are other ways to eliminate this uncertainty than to characterize the full delay, but if the racks are on opposite ends of a giant data centre, that might be as or more difficult than just going through those motions.

If you just have one GM, then sure, the delay means you will have a larger fixed offset from TAI/UTC, but that won't be consequential, and you'll still get the benefits of a tightly synchronized monotonic clock. Until that GM fails, and it all goes haywire.

GPS is receive only, the phone doesn't talk to the satellites, which just broadcast their signal to everyone. There is certainly a new radio (& ancillary equipment & antenna) in the latest model to support this feature.

It depends a lot on the terrain and specific area whether a typical VHF/UHF ham radio will work. The range is much longer than cellular, but it is quite LOS, and repeater/digipeater sites with good coverage tend to be at established antenna sites for commercical broadcast or telecom. There'll be some more remote sites of course, but infrastructure and LOS is still more or less required. With many popular recreation areas up in uninhabited mountain valleys with no infrastructure and where building stuff is often prohibited, the chances of hitting a site aren't great unless you happen to be below a mountain microwave site or such. At least without hiking out of the valley, but that's hardly a condition you want to put on yourself for an emergency communicator.

That said, it's not a bad thing to carry in your car, as there are plenty enough dead spots that would likely be covered by packet radio. It's just a lot less clear how to get help.

> And an excellent system involves collecting fare revenue from riders.

This is far from self-evident. There are at least two ways to fund such a system (and variants within), and most systems are funded by a combination of taxes and user-fees. Unlike roads, which are usually free at point of use, and this model should probably be applied much more often to public transport if we are to wean ourselves off driving everywhere.

> The answer is that you’re not spending it to halt X, you’re spending it to halt 10X down the road.

You need to justify this somehow to justify spending X > Y on enforcement. This is very far from self-evident, and my hunch is that these numbers are either relatively stable, or correlate with economic 'health' of the community, which is to suggest that the 'network effect' doesn't apply here as you suggest.

Your enforcers will not be (anywhere near) 100% effective either. At best, maybe you can expect to break even, but even that is probably difficult, and since 'breaking even' means significant negative impact on individuals, and has serious risk of scope creep and perception issues with the 'transit cops', it doesn't sound at all worth it.

What happens when someone gets caught dodging the fare and fined? They can't afford to pay the transit fare, and now they can't afford a fine that is, what, 20X the fare, and it just adds to their stress / debt load / collections coming after them. Meanwhile, since they can't afford it, they don't pay it, and the city doesn't actually collect any revenue from this endeavour. This is like library fines - the people who most need the system either get excluded from it or it even starts actively working against them.

Unless the system is running into capacity limits (or capacity break points), the marginal cost of freeloaders using the system is effectively zero; the trains run anyway. The ROI on paying for enforcement is almost certainly going to be terrible. It's very reactionary 'wrongdoers should be punished' thinking that doesn't actually solve anything.

Remember that governemnt services like public transit shouldn't be operated like for-profit businesess. The product of their efforts, and the way to judge them, is people transported, not dollars.