jackdaww wrote:confusion abounds !!
my smartfone sim is asda payg - very cheap and only used on holiday in june and september , i dont do bundles/contracts and the like.
It might be cheap for your usage in a phone, it probably isn't cheap for use to tether a laptop which will use *lots* more data *lots, and lots*.
jackdaww wrote:
my understandings are -- and any or all could be wrong ---
the asda sim is either not very suitable for data and / or data would be expensive and/or slow.
Expensive - probably. Not suitable - unlikely - normally only unlimited phone data contracts prohibit or limit tethering. Slow - unlikely - but it depends where you are are and the state of the mobile network there; central London - good, Highlands of Scotland - bad.
jackdaww wrote:a data only sim is meant for data and does not have an 07 number - who wants to call a data only sim ?
Yes the networks sell data sims meant for data, although they still do have a phone number and many can receive or even make calls. But the networks want to dissuade people from using them in phones, so call them "data sims" with all sorts of dire warnings. I have used data sims in dual sim phones for years without issue.
jackdaww wrote:a smartfone would not perform as well as specialised hotspot mifi device.
Probably not, but the performance hit is more likely to be on the WiFI connection to the laptop than the mobile connection to the phone network, although some do allow for external aerials to be attached which phones don't.
jackdaww wrote:this is whats behind my thinking of having a cheap payg sim in the fone and a data only sim in a device.
i also remember now when playing with smartfone tethering various modes eg GPRS EDGE UMTS HSPA which i never understood .
GPRS and EDGE - 2G (old fashioned) mobile phone calls - good for coverage, dreadful for 'volumes' of data.
UMTS/HSPA - 3G mobile phone calls - worse for coverage, better for volumes of data
LTE - 4G mobile phone calls - worse for coverage, even better for volumes of data
But don't fiddle with them, just let the phone / mifi do what it needs to do to get a connection