This question may sound dumb, but I am going to ask anyway.
I have tried many times to SMS from a GSM Foreign sim Local and International to a CDMA phone such as Verizion. The SMS always fails. IS it GSM to GSM only. and CDMA to CDMA only.
IF i were to say SMS Sinamon who has a t-mobile from my verizion account would he get the SMS? Just wondering why my SMS have not worked. :unsure:

I believe I can send & receive SMS within Us to ANY network. I have send and received SMS from Sprint and, I believe, Verizon.

From and to foreign countries the matter is not so simple. I am lead to believe that with Sprint one MAY be able to send an SMS to a foreign phone. I believe the pattern is 011 etc not the +. I have not tried sending FROM Verizon.

Stan

My experience is that almost all US carriers interchange SMS with almost all other US carriers. US GSM carriers also interchange SMS with their GSM roaming partners. Foreign carriers may be ignorant of US carriers with whom they have no roaming agreements (i.e. CDMA carriers). Same situation in Japan. SMS seems to work only with the WCDMA side of DoCoMo & Voda.

Yes, in GSM world usually the following is true: roaming agreement <=> SMS interchange. For GSM <-> CDMA SMS interchange, I suppose that extra agreements are needed (and possible extra software for setting some kind of GSM/CDMA gateway).

In Nov & Dec 05 I made some tests of GSM/CDMA SMS interchange from Plus GSM, Poland (this operator offers sending SMS to some non-GSM operators in USA and Canada at regular international SMS rates - no surcharges for GSAM2CDMA "conversion").
I forgot to post the results :whistle:, however, they were not very satisfying.
Now it's a good occasion to tell a few words about this "experiment" (quotations are from PM).

Harryb (quotations are Harry's)
Plus GSM -> Verizon CDMA
"My phone received the message promptly"

Verizon CDMA -> Plus GSM
"I looked into why you did not get my SMS and found that VerizonWireless customers can send International SMS to only certain countries. Poland is not one of them. Reviewing the list I cannot see any logical pattern. Most of the western European countries are included in the list, but I could not find any of the Eastern European countries on it. Also no Russia and none of the former Soviet Republics. Most countries on other continents are included with a few exceptions."

DRNewcomb
Plus GSM -> Cellular South CDMA
"I've just sent it and received the delivery report 'Discarded' " (this MY message to DRN).
Cellular South CDMA -> Plus GSM
test not performed (PM got lost in the cyberspace) but I suppose the SMS wouldn't get through in this direction either...

The US operators subscribe to a service like Mobile365.com which translates messages from one type carrier to another. Anything T-Mobile does not recognize as GSM they send to the clearing house. This is why, if I send a SMS to a random number, (e.g. POTS, non-existant number) it reports that the message was delivered and bills me for the experience.