SMS: what does "Dialing Mode for SMS" setting do?

Help & Support
1

In the “Message Service (SMS/MMS)” section on the Manage DIDs page, there is a setting named Dialing Mode for SMS (API). What’s it for? There are two possible options: NANPA and E164. Does it have anything to do with using the voip.ms softphone app for sending SMS messages? I want to be able to send SMS messages to European numbers, for which the E164 format is preferred. It’s the same format used to dial international voice calls on cellphones: +.

The Wiki topic on SMS suggests that voip.ms doesn’t support non-North American destinations, but if that were true, it’s not clear why there would be an option for E164 when addressing SMS messages.

2

It tells the API what style of phone‑number formatting you’re going to use: NANPA means you send a 10‑digit North American number, and E164 means you send a full “+country‑code” number.

3

Is the API used by the Messages feature of the VoIPmsSoftphone app?

Or is the API used for some other programmatic interface to the voip.ms system?