Okay, I think we're talking past each other a little bit here. First of all, Sprint does not have any type of mobile originated SMS functionality period. Unlike Sprint, most other wireless providers (gsm etc) have a completely separate system which handle SMS send, traffic, forwarding, response etc. This system is totally separate from the voice or wireless data (gprs) systems of the provider. Thus you never have to log on to data to send a SMS. Sprint (stupidly) does not offer anything like this. Having said that, when you send a SMS, you're esentially sending it to a mobile email address. For example, if you want to send a SMS to a Tmo phone from your email client, you would send it to TMobile_number@tmomail.net. Below are all the sms email address of various carriers:

Alltel: @alltelmessage.com

AT&T: @mobile.att.net

Cellular One: @mycellone.net

Cellular One [Amarillo, TX customers]: @wwtext.net

Cingular: @mobile.mycingular.com

HickoryTech: @sms.hickorytech.com

Fido: @fido.ca

Nextel: @messaging.nextel.com

Qwest Wireless: @qwestmp.com

Sprint PCS: @messaging.sprintpcs.com

SureWest: @mobile.surewest.com

T-Mobile: @tmomail.net

Telus Mobility: @msg.telus.com

Verizon Wireless: @vtext.com


What sprint has is something called short mail and one-way text messaging. For short mail, you phone has to be connectted to vision (i.e data capable) in order to send/receive messages. On older 2G phones, you have to log on to Sprint's WAP portal to send/receive messagess. Text messaging is just one-way and is meant to be sent from the SprintPCS messaging site only! With text messaging, the receiving mobile must be data capable as well. Thus both methods utilize vision (1xrtt) regardless. The interesting thing is what apps like Treo300SMS can do on palmOS smartphones. With Treo300SMS, I can send/receive both shortmail and text messages from my treo, not just the website. For example if I receive a short mail message from another sprint mobile, Treo300SMS automatically registers the presence of the mail, activates the retrieval program whereby the SMS app logs onto vision, downloads the short mail and presents it in a sms popup window on my screen. You can than either reply to the short mail, call back the sender, or delete the message. Thus Treo300SMS integrates SMS-like functionality to short mail. If someone sends you a text message from either the SprintPCS messaging site or by sending an message to xxx-xxx-xxxx@messaging.sprintpcs.com, the message is directly sent to your mobile without having to log onto vision. However, if you want to reply, Treo300SMS has to log onto vision where it sends the text message through its proxy to the Sprint servers. This logging on/off vision usually isn't a problem if you just keep your vision connected 24/7. This does not mean you wil miss calls though (at least on the Treo). While using an active vision connection (green arrows), the treo will give you the option of answering the call or ignoring (unless you're out of coverage) where it then goes to the voicemail. Otherwise while in a state of non-active vision (grey arrows), the treo answers normally. Thus AFAIK, you don't miss calls while on vision. That's why you can keep vision connected 24/7...

Anyway, that's how Treo300SMS works and I presume this is how i500SMS should work in the future once PDAapps releases it. I hope I didn't confuse anybody and if I stated something incorrectly, please let me know...