US/UK device compatibility - phones/iPads etc.

[Dave2002]

Wanted for a future visit to NY.

1. Confirmation that some/most USB devices can be charged from a "UK" charger. For example, my iPad charger says it should work from 100V-250V 50Hz-60Hz and give an output of 5.1V. I presume therefore that if it's plugged into a US/UK travel converter plug, it should still work safely and charge up an iPad.

I'm not sure whether the same compatibility will apply to phone chargers - but I'm now going round mine with a magnifying glass to check. If it comes to it, the phones could be charged from an iPad charger anyway I think.

2. Advice - if possible re iPad SIM cards. In the UK it's possible to get SIM cards which last for a short period - such as by Vodafone or 3. The 3 PAYGO cards allow up to 3Gbytes of downloads for up to 3 months as I recall, and cost around £21.

Are similar iPad compatible SIM cards available in the USA at a reasonable cost - say between 15$-60$?
If so, which companies do them, and were can they be bought from?

[richardfinegold]

Hmm, I didn't know that the ipad took a SIM card, so I guess I'm not the person to ask
You know that all things Apple won't work over here without adapters, right?

[Dave2002]

Hmm, I didn't know that the ipad took a SIM card, so I guess I'm not the person to ask
You know that all things Apple won't work over here without adapters, right?

Over here the models with 3G or 4G do take a SIM card, and that even includes the 1st Gen versions. I thought that the US had now converged to some extent with Europe, at least in so far as making it possible for mobile devices to have a SIM card which enables them to work with multiple operators by swapping the cards. This is apparently quite common in some countries - see https://en.wikipedia.org/wiki/Subscr...dentity_module

We have used mobile phones since the early 1980s, but they were analogue. We personally have used digital mobile phones since the late 1990s, and there was an explosion in the use of digital phones from the mid 1990s on. The linked article shows that the earliest deployment of SIM cards was in 1993.

From what I have read, it is possible that earlier phones and mobile equipment made for use in the US did not have SIM cards. Perhaps they were hard wired, or maybe they had some similar form of memory device internally, which was not user swappable. This could have been for technical reasons, or because standardisation in the mobile industry was incomplete, or a deliberate attempt by interested commercial parties to segment the market, and hence to increase revenue for individual subscribers. In some markets, such as in the UK, mobile devices were sold at below or about cost price, with network development costs then paid for by an increased subscription. In the UK this required a very specific legal framework to be set up even for analogue phones. Initially only a subscription business model was used, with service providers locking customers into (typically) an 18 month or 2 year contract. As eventually the networks were developed, I think it was felt that the market was saturated, so the PAYGO (pay as you go) business model was rolled out, and this does now seem to be viable. The manufacture of mobile devices is now seemingly considered to be relatively low cost so that it is no longer essential to subsidise their cost of development and manufacture by "enhancing" the operating costs, though phones used on PAYGO contracts may have a significantly higher up front cost.

Some service industries, such as phone and railway businesses, have historically initially "suffered" from lack of infrastructure provision and lack of a large customer base. In the case of phones, at start up there is "nobody to talk to", and in the case of some early railway systems, such as the London Underground "there's nowhere anyone would want to go." Despite that, some such businesses have been very profitable, once they have passed the start up phase.

Currently I think it should be at least technically possible to take a mobile device, such as a phone or iPad, to the US, and fit a new SIM, though whether that can be done for tourists who may simply be passing through for a short while I don't know. It is possible, I hear, in most European countries now.


Re the power adapters, examining the fine print on several phone and iPad adapters suggests that most are universal with something like "input 100V-240V output 5.1 V 0.3 amp" written on them. Often these are made in China it would appear. There is clearly incompatibility in mains power plugs between many different countries, but that is usually solved by travel adapters

So, I'm coming to the conclusion that chargers for mobile devices such as phones and iPads should work between the US and UK with only the use of a cheap travel plug adapter, and there should be no need to purchase or borrow country specific chargers for working with USB powered devices requiing a 5V (5.1V) power source..Tecnically most chargers now seem to use switch mode power supply units which are cheap, rather than mains transformers which were used a few decades ago.