PAYG SIM minutes don't run out - no monthly top up

That's interesting. I couldn't find that stated anywhere a month or two back when I was researching it.

Cycles per second is the same thing as Hertz. Hertz was defined in 1930 apparently, and has been the SI unit of frequency since 1960, but seems to have taken a while to catch on...

Mike

Virgin certainly used not to.

My first ever mobile phone in 2002 was on Virgin and that SIM still works today even though it's only been topped up once since about 2008. It's in my emergency cheapo backup mobile phone which I only switch on very occasionally to see if it still works.

Have you actually tried to make a call ?

There *may* be a facility such that while the individual numbers may be lost - the networks may somehow retain the facility to contact all their live SIMs i.e SIMS that are powered up if only ocassionally.

michael adams

...

In particular 3 was the ONLY company that did wifi calling on a PAYG sim. You need the right phone though, and it has to be 3 branded.

If you have wifi calling, text will work too. Text is just a low bandwidth voice call really.

I don't think it needs to be explicitly stated.

pity it's a townie network

that's a shame...

bloody German crap...

or go out into the wilds where only a 900Mc/s network works ...

how does that work?...honest question

interesting

who remembers vodaphone when you had to pay for line rental as well as calls ?...on payg

Well Vodafone haven?t mastered the art of Wi-Fi SMS although they can do Wi-Fi voice.

works fine for me.

Perhaps so, but I have seen several statements that WiFi Calling on O2 doesn't pass text messages, and no statement, least of all from O2, that it does.

"WiFi Calling" needs the right firmware in the phone. Perhaps early versions didn't have SMS capabilty. Or the operator selectively enables it, or not, depending on the tarrif(*).

And how do you *know* the SMS arrived by WiFi not the normal 2/3/4/5G way? SMS will get through in areas where voice is unuseable.

(*) Asda Mobile (EE) only allow call divert to answerphone. You can't divert to say your landline number. On TPO (EE) you could divert to your landline.

Same as VOIP as far as the message passing I suppose. Whether either the network or the phone use DNS and ipv4 or ipv6 or some other method to find each other I have no idea.

SI units were taught when I was in school (incl Hz) and I'm now an OAP!