From AAISP Support Site

This page gives an overview to using our services for SMS.

Inbound SMS

This is where text messages are sent to us to deliver to our customers. We provide VoIP numbers in mobile range (07) and in all UK area codes and some special services (e.g. 0800). However, at present, only mobile numbers, and a few of the numbers starting 01 and 02 can receive SMS messages properly from most networks. All of our 01, 02 and 03 numbers can receive SMS messages from Three properly, it seems. Attempts to send SMS messages to other geographic numbers (i.e. those starting 01 and 02) cause a call to be made and the SMS message read out by an automated system.

Where SMS messages can be received properly, and this includes all cases where A&A customers send SMS messages through us, the SMS message will be sent on to you by your choice of means. This is based on the incoming SMS message setting in the control pages for your number.

Accessing This Feature

Access is via the Control Pages as follows:

  1. Log in to the Control Pages with your xxx@a login
  2. Click on the number you want to manage
  3. Click the Incoming tab, scroll to the bottom of the page
  4. Enter the details into the SMS Inbound box
Inbound SMS option on Control Pages

You can put multiple targets separated by a space. See SMS API for how these work.

  • Email address - emails the SMS
  • Fediverse address - toots the SMS (as a direct mention)
  • Mobile number - sends the SMS to another mobile number (chargeable)
  • Web URL - sends the SMS as an http/https GET/POST
  • SIM ICCID - when offered, sends to a SIM directly (SIP2SIM)

Outbound SMS

Any of our VoIP Numbers can be used to send SMS messages. Just beware that not all numbers can receive an SMS message.

You can send in the following ways:

Multipart texts

Where possible multi-part SMS messages are automatically handled, concatenated before being passed to you, or split from your message into parts. Unfortunately, not all of the systems to which we interconnect handle multi-part messages sensibly, and this can result in a multi-part message being delivered as multiple separate messages.


The whole of the traditional telecoms network has limited privacy, in that connections are not generally encrypted and may pass through several telcos, and of which could listen to calls or access SMS. The over the air radio parts of mobile calls and SMS are encrypted (though not always very well). However you should also consider privacy when forwarding SMS outside the telecoms network.

  • Sending SMS to us, use https to ensure encryption to us.
  • Sending SMS from us to a web form, you can use http, but that is not encrypted, so we recommend https.
  • Sending SMS from us by email may use encryption between email servers, or may not, and mail server operators could access messages.
  • Sending SMS by fediverse, communications are normally encrypted, but instance operators could access messages, even though sent as a direct mention. If you trust your instance operator (or run yourself) this should be reasonably secure.
  • SMS CDRs (itemised billing) show the texts, see below.

Itemised billing

Your bill will show the number of SMS messages sent and received per number. The optional XML/JSON version of your bill contains detailed information for each message sent or received, including the text content of the message (unless the private setting was used).

Multipart texts are itemised and billed as a single text but billed for the number of parts sent. The XML identifies the number of parts.


The originator field is used to set where the message is from. Normally this is only your phone number. Exceptions are:-

If you have a presentation number set up for your VoIP, this will be used unless you specify an originator. You can specify the presentation number, or the main number. If you ask us, we can allow sending of text-based originators on a per account basis. You will need to be an established customer. This can be withdrawn at any time.

UTF8 Character Sets

The SIP2SIM service does handle all of the GSM character set options, including the 7 bit character set with escaping, the 8 bit binary messages (assuming latin1 character set), and the 16 bit character set with UCS16 surrogates for full unicode.

Internally we convert all messages to UTF-8. If we are sending messages to your own gateway or email they will be in UTF-8.

Our outgoing SMS carriers to external mobiles do not support everything, sadly, and so some characters may get lost on the way. We can only suggest testing yourself to confirm.

SMS error codes

This is a list of internal error codes which may be shown on CDRs if something went wrong:

  • -201 no target found for incoming SMS to customer
  • -204 error while HTTP posting to customer's server
  • -202 and -203 invalid destination email address
  • -301 no destination number
  • -302 and -303 no SMS content to deliver
  • -304 this is a status report, not a normal SMS
  • -305 message billing error - eg we won't send the message as we don't know who to bill
  • -306 too many message parts
  • -702 failed to route message - possible if sending to a totally invalid number
  • -801 and -802 are decoding errors while packing to TPDUs
  • -803 originator address not allowed