interesting wifi anomaly

Factual Questions
1

this is a factual inquiry but a really dumb one, so i hope it belongs in GQ.

TL; DR version: **how is it possible to send SMS messages from my cell via a wifi router that has no internet service? **(i did this. it worked).
explanation:

i live in a large warehouse with a single DSL service line in for the internet. we spliced it at the source via a line splitter so a wire goes to the flat where i reside into my wireless router and the other line goes to the main office of the building into a hardline modem that is only turned on when the office is open.

att dsl infrastructure is such that when the hardline modem is turned on in the main office, it will trump the wifi router in the flat. basically if someone turns that modem on, internet goes through it into the office computers and the “no signal” light flashes on my wireless router. i do not have internet at all until the hardline modem is turned off again. i have never ever been able to circumvent this, and after speaking to tech support i was told that is how the system is set up, so unless we can use a single router for both computers, we would need a separate line to keep both modems functional at the same time.

all this means is during open hours, i never have internet. whatever.

my cell phone is a smart phone that allows wifi connectivity.
i made a mistake and my service was discontinued for a day.

so, no cell service. also, no internet (dsl diverted to front office).

goofing around, i turned on wifi calling and connected to the live router (you can still connect to the router’s signal even without internet service coming into it).

to my surprise, it allowed me to send SMS messages.

so the question is–HOW? what?

is SMS a tiny amount of bandwidth and my DLS connection had some fractional amount of oozing internet still coming in that allowed it–even tho it won’t let me online and the “no internet service” light flashes?

or is there dark wizardry afoot?

2

If your provider is Sprint, they will often allow SMS but not internet, if you don’t pay your bill.

Other than your provider having a policy that allows SMS but no data, I would guess that your provider might have made an error.

3

i have tmobile, and the SMS went through the wifi signal, not my cell phone’s service.

since the internet was rerouted to the hardline modem, the only thing i can think of is 1. the way DSL and multiple modems works is the bulk of bandwidth goes to the hardline but some tiny, SMS-sized amount still came to the wifi router. or, 2. magic.

4

right now i am leaning towards “magic.”

5

How do you know this?
SMS is purely a cell phone protocol. The only way to send an SMS through the Internet is to use a gateway.

6

because my cell phone service had been suspended. it was turned off for the entire day before as well as the day-of. my phone was useless until i turned on wifi-calling and tried to send the text using that.

SMS and phone calls can be placed via wifi signals for wifi-compatible phones. they circumvent your cell service and piggyback on the wifi internet signal (there is debate about this because you dodge using plan minutes this way. some providers make you pay a fee to allow wifi calling).

in this particular case, the dsl internet connection was diverted to the hardline modem, so my wifi-router was receiving no internet signal (it was flashing red “no signal.”)

yet somehow i was sending and receiving SMS texts via the wifi connection.

again, the only way this makes sense is that some tiny fraction of bandwidth was still allowing the sms to get through, but i do not know enough about how DSL works to confirm that.

i thought someone here might know…

btw there’s a lot of ways to send SMS over the net, but that’s moot to the point–i was using a serviceless cell phone through wifi calling…

7

btw on my phone model, when you flip the touchscreen “switch” that turns wifi calling on, it turns off your cell provider. the cell signal indicator is replaced with a wifi signal indicator.

to be clear, there isn’t any chance the phone sent the SMS via my cell provider. that’s not the question. the question is how wifi sent the data without the internet being active…

8

I simply don’t believe that you are correctly analyzing what happened.

9

Yeah, if you want to know what happened, you’re going to have to try replicating it under controlled circumstances. Make sure your cell antenna is off by directly disabling it, then try sending an sms from different wifi locations, such as a free hot spot away from this building. Try it when the your place is open and closed. Make a note when you send and when they receive.

Also, it sounds like your dsl routes through another dimension, so I really recommend finding a more robust method, just to maintain your sanity.

10

based on what factors?

eta: just tried it again, with the thing unplugged. it works.

i am uploading photos…

11

i just tried it by turning every service but wifi off on my phone.

i unplugged the DSL line from the modem altogether, so there’s no possible internet signal going through. then i sent a test-text to myself.

it went through.

pics:

screenshotshowing my mobile network (tmobile/cell service is not turned on. no service but wifi is on)

screenshotshowing that no other wifi-signals are within range (i live in a warehouse in an industrial zone).

photoof my modem/wifi router with the DSL cord laying unplugged over it.
and, finally, screenshotof my sent/received text (note the time stamps for all screen shots, it is now 12:14 am and all of this happened in the last 20 minutes). the “words” texts from this afternoon were my first wifi-internet-free tests texts. also note: the timestamp 11:58 is the same minute of both screenshots of the text sent and received and the screenshot of the cell network turned off.

so. how the hell? how can you send SMS thru an internetless wifi router…?

12

i would also like to clarify i sent other texts to other people–four other people, to be sure it wasn’t just my phone getting it’s own messages. they all received and replied to the texts. i can’t really post screenshots of their phones, so this will have to suffice.

so it seems simplified–something about a wifi router allows for sending SMS even without internet going to it.

so i guess now we just figure out how that is possible…

13

Your cell service is not off. Your data service is off in that screenshot, but not phone service, which is what SMS uses (I just tested myself with my phone–turned the Mobile Service off, lost my 4G indicator, but still could make calls)

14

You lost me with the building internet architecture explanation. It doesnt make sense. Be specific into what plugs into what. The business modem only works 9 to 5? Ive never heard of an electronic device working human hours only. Your wifi router plugs into where? Normally you need a modem to plug into the wall phone socket. Lastly the only signal interference that ive encountered is between digital (routers) and analog wireless phones (90s style).

Eta: why are you splicing wires and some such? That’s what routers are for.

15

it’s a complicated DSL set up, but that doesn’t matter at this point. i just posted a photo of the DSL line unplugged from the modem showing that no possible amount of internet service could be coming into the wifi router/modem, yet it still allows me to send SMS.
if you really want to know about the building, here comes a ton of stuff. it seems moot at this point, so dont’ read unless you want–
it’s an old warehouse. we have DSL. it comes in through a phone jack. we put a jack splitter in that plug and run two lengths of phone (dsl) cord to very distant areas of the building. in my area, i have a wifi router/modem (all in one unit). in the office, on the other end of the split line, there is a hardline modem that is only turned on when people are in the office. DSL runs into the building all the time, but when the office modem is on, it takes all the internets. my wifi end just flashes “no signal.” ATT said it is because their standard-issue hardline modem is set up to be the “main” modem, and this makes it so people cannot split a single DLS line and run it to as many modems as they want. when no one is in the office (closed hours), i have full time internet because the signal is uninterrupted and goes to me.

in a house-type setting, a wifi or router would be enough to allow multiple computers to connect from a single dsl line. but due to the logistics of the building and the metal construction, we can’t have a single wifi unit that will broadcast a signal. so, because of all that, i don’t have internet when the office’s modem is on.

regardless, i just experimented. the fact remains you can send SMS via a no-internet wifi modem.

so. how?

16

except my cell service was cut off due to not paying my bill on time. and i tried several times to send texts before trying the wifi thing (i had a meeting and needed to contact them. that desperation is why i tried this). each text attempt just showed a red triangle with an exclamation point in it and said “text not sent.”

i just turned the network service off to be sure it was off. but t-mob had actually cut my service on their end.

eta: if you have a suggestion for how i prove the service is off, let me know, and i’ll try that.

17

hmpf.

In that case, this is simple and the sms is going out the 3g/4g antenna.

18

another key point is that MMS, email connection and other web browsing was not possible through this set up. only SMS. one of the test persons tried to send a photo but it just came up as “unable to retrieve.”

19

is that possible when your cell service has been suspended?

why does it only work when i turn on wifi calling on my phone?

20

Could be either a bug or a feature.