Possible to detect SMS carrier automatically?

[fubowl]

I am well aware of how to send text messages using php's mail() command:

 

<?php
$from = $_POST['from'];
$to = $_POST['to'];
$carrier = $_POST['carrier'];
$message = stripslashes($_POST['message']);

if ((empty($from)) || (empty($to)) || (empty($message))) {
header ("Location: sms_error.php");
}

else if ($carrier == "verizon") {
$formatted_number = $to."@vtext.com";
mail("$formatted_number", "SMS", "$message"); 
// Currently, the subject is set to "SMS". Feel free to change this.

header ("Location: sms_success.php");
}

else if ($carrier == "tmobile") {
$formatted_number = $to."@tmomail.net";
mail("$formatted_number", "SMS", "$message");

header ("Location: sms_success.php");
}

else if ($carrier == "sprint") {
$formatted_number = $to."@messaging.sprintpcs.com";
mail("$formatted_number", "SMS", "$message");

header ("Location: sms_success.php");
}

 

My question however, is if anyone knows how to detect the carrier automatically WITHOUT input from the user. I know gmail allows the ability the only enter the phone number and it goes to the correct carrier, but how do they do this without knowing the carrier? Do they simply send the sms to each carrier or do they have the knowhow to send it to the carrier based on the phone number itself?

 

Thanks.

[Pikachu2000]

You have to send email to a valid email address. A phone number is not a valid email address. Since number portability kicked in, there's no reliable way to deduce the carrier from the number either.

[fubowl]

So you think that gmail is just sending them to every possible carrier @ once?

[Pikachu2000]

No. Google can well afford to send the SMS messages directly. I seriously doubt they're sending out emails to the carrier to get a message to a phone.

[premiso]

If you want this functionality you will need to look into an SMS Server or SMS Gateway, mind you it will cost a pretty penny to get started up with it.

[fubowl]

Thanks very much for your responses Pikachu2000 and premiso.