Hi together,

since about 2 weeks, I have a big issue to send SMS from my dtac prepaid sim to Switzerland. 95% of the sent SMS don't reach the recipient in Swiss (I tried to send to any operator and changed my mobile too) but every missed SMS was charged with the usual 8.56 Baht. When a SMS was sent correctly, it shows not my dtac number but one who starts with +1xxx! The dtac call center couldn't help, only '..switch of and on your mobile...' blablaba!

Maybe someone know about this problem?

Thanks, Pit

Perhaps check that you have the correct SMS Message Centre number set up in your phone. I think it is +66942500500 but DTAC can confirm.

Is the person at the other end roaming or on a Swiss number?

If roaming, they need to make sure they are always connected to a DTAC partner.

Thanks for your answers!

I will check the the SMS Message Centre number, but if it's the wrong one, it's strange that a few SMS are received.
The numbers in Swiss are all from Swiss providers, not roaming.
I tried to send SMS with 12call and True now, no problems at all, every SMS was received and shows the correct phone number. Next I buy another dtac SIM, although I don't want loose more money with them.

SMS, technologically, is a terrible system. The service provider can't even guarantee delivery within a country, much less internationally. What you're describing seems pretty much par for the course (the target recipient simply moving in and out of coverage between cell towers, such as while being on a train, would be sufficient to cause this kind of problem, much less roaming between different carriers per the other poster - by "roaming" it doesn't have to mean connecting to a non-Swiss carrier, but handing off between different all-Swiss carriers is enough to cause problems).

Do you and the recipient both have data/internet access on phones? It often comes as a surprise to many but the "free" services are actually more reliable in terms of delivery (plus you get to see indications for delivery, and if the messages have been read) - iMessage, WhatsApp, Line etc. (categorised as "OTT" services) are in fact more flexible and more reliable.

I would think this is more of an International SMS Gateway issue (inter-network) between DTAC's network and those abroad.

Commercial Roaming Arrangements are required between Mobile Carriers in order to facilitate the exchange of SMS messages between them, and have proven pathways to convey them. You may have proved this is the bottleneck when you tried two alternate mobile carriers with no issues in delivery or reception.

If you are really glued to using DTAC then make sure all the 'settings' are correct, and if so then ask how to lodge a 'trouble ticket' with them.

OR... get a dual-sim phone and put an AIS or TrueMove-H SIM in and use that for sending/receiving SMS.

Removed an off-topic post.

Also, since about 3 days sending SMS with dtac works again so far. I shows my correct dtac nr. on the recipient phone. What has changed is that before the issue, it shows the Thai local time of the sent SMS, now it shows the local time of Switzerland.

I wonder what dtac played around and when it will happen again!