[Scoundreller]

Knowing which numbers are capable of receiving SMS and which aren't has some value.

Especially in a world of number portability where you can't just say "oh, that's an old number, it must be POTS".

But I guess, here, if a number is from your contact list, it may still be POTS.

But at least you have higher assurance that it's an active user. If you wardial one day, you quickly find out how many numbers never lead to a human for various reasons. In theory, some of these are trap numbers and quickly flag the caller as suspicious, but I doubt it.

[rsync]

"Knowing which numbers are capable of receiving SMS and which aren't has some value."

This isn't difficult - I wrote a shell script named "lookup" that will give me background info for any phone number I feed it and tell me what kind of number it is, what carrier it is, who it belongs to, etc.:

  # lookup 415-333-2222

  {"caller_name": {"caller_name": "WIRELESS CALLER", "caller_type": null, "error_code": null}, "country_code": "US", "phone_number": "[phone]", "national_format": "[phone]", "carrier": {"mobile_country_code": "311", "mobile_network_code": "489", "name": "Verizon Wireless", "type": "mobile", "error_code": null}, "add_ons": null, "url": "https://lookups.twilio.com/v1/PhoneNumbers/[phone]?Type=carrier&Type=caller-name"}

... which is very useful since I often send (personal) SMS from the command line and sometimes I need to know if a number can receive it ...

I'm not going to paste the entire script here but the meat of it is:

  /usr/local/bin/curl -X GET "https://lookups.twilio.com/v1/PhoneNumbers/$number?Type=carrier&Type=caller-name" -u $accountsid:$authtoken

... and each lookup costs a penny or a half a penny or something ... I forget ...

[EGreg]

How would your script obtain this information though? Relying on twilio?

[rospaya]

In some countries mobile phone numbers have a prefix so you know by that.

[gsich]

Also some POTS provider will accept SMS and either read it to you, or you can read them in some web portal (or the router possibly).

[simfree]

The Local Routing Number provides this value in the USA, and multiple carriers (eg:Twilio) offer daily deactivation reports from the cellular carriers so you can tell which numbers are unroutable.

[Scoundreller]

Canada isn't as progressive. Only telecoms can see which telecom a number points to and for the purpose of call-routing only.