Kitz Forum

Computers & Hardware => Android & other hand held devices => Topic started by: jelv on October 08, 2021, 03:42:33 PM

Title: How (I'm baffled)?
Post by: jelv on October 08, 2021, 03:42:33 PM
Removed the SIM card for a handset running Android 9 and put it in a different handset.

Rang number from another phone and it rang - tick.

Tried sending an SMS text from the new handset which was received - tick.

Sent an SMS text to the phone number - didn't get through.

Powered up the original handset (without any SIM) and it received the test text.

How can a phone without a SIM receive text messages?
Title: Re: How (I'm baffled)?
Post by: g3uiss on October 08, 2021, 03:46:32 PM
Via wifi ?
Title: Re: How (I'm baffled)?
Post by: jelv on October 08, 2021, 04:03:27 PM
Just tried again with WiFi off and no message received, turned WiFi on and it came through so you are right. Isn't SMS a mobile phone network feature, not an internet feature?

Text messages are sent to phone numbers, how can the handset know it's number to receive messages without a SIM?
Title: Re: How (I'm baffled)?
Post by: g3uiss on October 08, 2021, 04:26:13 PM
It was originally. However over the last few years like calls can be routed over wifi so can some messages. It’s all ways been  so with iMessage I guess Android has something similar. There must be a setting somewhere to turn feature on or off. You need to remove from the old handset !
Title: Re: How (I'm baffled)?
Post by: licquorice on October 08, 2021, 04:34:08 PM
Wifi calling was the gist of the reply I deleted, but then I thought about it and came to the conclusion that even with wifi calling a Sim card would be needed as the phone is just connecting to the mobile network via the ISP rather than directly to a mobile signal.

No other suggestion  ???
Title: Re: How (I'm baffled)?
Post by: jelv on October 08, 2021, 05:49:33 PM
WiFi calling did cross my mind, but the original phone doesn't support that.

I'm wondering if it does it via the IMEI or similar and maybe that was cached by whatever server(s) does the routing of text messages. I went off to do something else for an hour or so and then tried again without changing anything and the message went to the new handset which would support that theory.
Title: Re: How (I'm baffled)?
Post by: Ronski on October 08, 2021, 06:49:59 PM
Is it using Google Messages (https://play.google.com/store/apps/details?id=com.google.android.apps.messaging&hl=en_GB&gl=US)?

I believe that's more like a proper chat app such as WhatsApp but will also send traditional SMS messages to mobiles without it.
Title: Re: How (I'm baffled)?
Post by: jelv on October 08, 2021, 07:31:54 PM
I think that's the answer. I've always thought it was a SMS app. The handset it was moved to hasn't a google account set up.