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An iPad does not support SMS messaging which is strictly a voice cell technology. There are SMS apps in the iTunes Store but whether any of them work well I can't say.

Regards.

iMessage only works from one iOS or OSX user to another. I have numerous international numbers with whom I use Facetime and iMessage.

As varjak paw said, SMS messaging is not supported by the iPad. There are several services that you can use to mimic SMS texting, but they cost money above and beyond the cost of your own service.

Yes, it says precisely what I said. You can use iMessage to send text messages to anyone using Apple devices that have iMessage set up.

I have been very clear, so have the links that you provided. Using iMessage, you can send messages to anyone with an iPad, iPhone, iPod or OSX (Mac) that has Messages or iMessage set up. You cannot send these messages to anyone else, including those who are using Android phones, Windows phones, Nokia phones, or whatever else is out there. It is an Apple only messaging system.

An iPhone can send SMS text messages to whomever they want, since they are on the cellular system. They also can send iMessages which avoid the cost of SMS text messages.

Is this not clear?

iMessage uses the Internet (through Apple server) to send text, images and videos to another Apple device.

If the recipient do not have an Apple device or it's not activated, it will fallback to SMS/MMS if the caller is an iPhone. An iPad is not a phone.

I think I get it now. iMessage only works with the iPad if:

a. you have iOS 5 or greater,

b. you sign up to iMessage

c. the people you send messages to are also signed up to iMessage.

Your A,B and C are correct.

It seems to be similar to Viber or Magic Jack.

Yes, they all uses Internet, but the underlying technology is different.

Furthermore iMessage it's free and it will sync across all your Apple devices.

Can anyone suggest how to test messaging if they have an iPad, not an iPhone?

You can use the Apple ID to activate your iPad's iMessage.

Tell your friend with an Apple device to send you a message by using your e-mail address (instead of a phone number).

Don''t know if the phone number in your iPad settings is your iPad cellular number. You have to call your carrier to comfirm. Anyway iPad uses the e-mail address for FaceTime.

You cannot use a phone number to setup FaceTime on iPad.

But you can make a FaceTime call to someone using his/her phone number provided it is an iPhone and FaceTime is configured.

The phone number is associated with your iPhone, if you have an iPhone. If you do not have an iPhone, then there would be no phone number in that list.

If you had an iPhone and set it up for iMessage, it automatically populates that number across all of your iDevices, including your iPad. When I got a new iPhone with a new phone number, I set it up with Messages. Immediately I opened up Messages on the Mac and on the iPad, and it asked me if I wanted to add my new phone number to the iMessage list. So, I have two emails (they're actually the same email, with just me.com and icloud.com) and my phone number.

I can tell when someone is using Messages because when I'm typing the message to them, it is in blue. When someone isn't on messages (on my iPhone at least), it's in green.

I hope this helps.