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Sim doesn't seem to work in dumb phones?

2: Seeker
2: Seeker


I recently switched from O2 to Vodafone. I have a Sonim Xp5700, which worked fine with O2 but with Vodafone the reception is flakey, when people call me it either tells them my phone is switched off or they can't hear me when I answer. If they can get through the reception comes and goes. I tried putting the sim in a smartphone and it wasn't as bad, it seemed to work okay. I also tried it in a Nokia 110 and the problem was still there. It seems like maybe the sim doesn't like dumb phones. As expected Vodafone's online help has been less than useless, they don't even know what a Sonim is, they think it's a Sony Xperia!

The phone is showing a full signal and according to Vodafone the reception in my area is good. I would like to continue using my Sonim phone, does anyone know what could be causing the problem? (I've been considering going to the nearest Vodafone shop but it's forty miles away, if the staff are as clueless as the online lot it would be a wasted journey)


4: Newbie

You mention "the reception is flakey" but also "the phone is showing a full signal". These appear contradictory statements - can you clarify the indicated coverage? Is there any onscreen indication of which radio technology (2G or 4G) the phone is using?

Is the phone a UK-spec model? I suspect that model doesn't support all of VF-UK's 4G bands.

The phone is using 4g and the it shows a full signal. I mean that when I am able to make or receive calls they frequently cut out.

Does the 4G display remain, when you're on calls? Or does the screen show VoLTE anywhere?

If not, the phone is using CSFB to fallback to 2G for voice calls.

I don't know what any of that means.

@nikafia wrote:

I don't know what any of that means.

Can you answer "Does the 4G display remain, when you're on calls? Or does the screen show VoLTE anywhere?"

16: Advanced member
16: Advanced member

4G refers to data, it doesn't really come into play on regular mobile phone calling.  The phone that our OP has though is not designed for the UK market (despite being sold on Amazon), because of this it's pot-luck as to which UK providers it'll work with