John Todd jtodd at
Wed Sep 23 14:42:08 UTC 2009

On Sep 22, 2009, at 9:29 AM, William Herrin wrote:

> On Tue, Sep 22, 2009 at 11:59 AM, Scott Berkman <scott at>  
> wrote:
> [snip]
>> I believe there was another solution that involved direct carrier
>> connections, but these are most likely cost prohibitive in most  
>> situations.
> Any pointers on this would be greatly appreciated. I have a need for
> geographically redundant access to the same phone numbers in order to
> send and receive SMS messages. Even if I have to buy a pair of T1s
> that are 99.9% idle, it'd be worth it.
> Regards,
> Bill Herrin
> -- 
> William D. Herrin ................ herrin at  bill at
> 3005 Crane Dr. ...................... Web: <>
> Falls Church, VA 22042-3004

   This question frequently arises on the VoIP/Asterisk lists, since  
it is a question that VoIP service providers often wish to answer -  
"How do I SMS-enable my VoIP customer numbers?"

   In other areas of the world, SMS is much more easily tied into  
existing voice networks - in the UK (among others) for instance, SMS  
is possible over PRI connections, which enables "land lines" to send  
and receive SMS messages.  Clickatell, the company referenced  
previously, is based in South Africa.  Buying their service for  
delivery of SMS into North America means that your messages will be  
sent with a "generic" short-code, which is not guaranteed and has in  
the past even been blocked by carriers.  Users cannot reply to those  
messages, because many other companies are using the same short code  
return address.  If you look at their website, you'll see that if you  
live in one of a few non-NA nations, you can buy an actual phone  
number (not a short code) which can be used for high-volume  
bidirectional communication via SMS.

   Here in North America, we're basically out of luck unless you hack  
together a hardware-based SMS device, and even that may be not  
reliable since carriers explicitly state that their accounts cannot be  
shared, and a large number of SMS messages to/from a particular  
account may cause it to be disconnected without warning.  It appears  
to me that carriers have taken the stance that SMS should be for  
infrequent messages between actual fingers (no automation allowed!) or  
via short codes, and short codes involve a significant amount of cost,  
configuration, and even arbitrary approvals from the carriers on the  
use of a short code.  If you look at the form required for a short  
code request, you'll discover that it's not for generic use - it's  
geared entirely for ad campaigns.

   A few years ago I tried searching for SMS-enabled SIP telephone  
numbers (DIDs) and found that there was a new service available, but  
the monthly price floor was pretty steep.  I still have not met anyone  
actually offering the service, but I'm sure there must be resellers of  
it by now.  It was Level 3, offering SIP trunks with DIDs on them.   
Another company, Syniverse, was then SMS-enabling those numbers in an  
exclusive agreement.  Payment had to go to each company, separately.   
The costs per number to enable SMS were fairly low, and the costs for  
message transmission were fairly low, but the Level 3 minimum purchase  
price was quite high (imagine that you could buy a nice sports car  
every month with the "minimum payment".)  I have no idea if this  
service is still available, or how successful it's been.

   If anyone now has direct experience with a reseller or small  
distributor of this service, let me know - I'm still looking for a SIP- 
capable DID that can handle SMTP/SMPP/XML-HTML transmission of SMS  
messages with some decent volume (200-1000 messages per day.)

Here's a message in a thread from a while back on this topic which has  
some pointers:


John Todd                       email:jtodd at
Digium, Inc. | Asterisk Open Source Community Director
445 Jan Davis Drive NW -  Huntsville AL 35806  -   USA
direct: +1-256-428-6083

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