Another WAP Push over SMS encoding

This entry is part 10 of 17 in the series Sending out an SMS

I still needed to show how you can send an Service Indication (SI) document like:

< ?xml version="1.0"?>
   <indication href=""
     si-expires="2009-03-04T16:25:00Z">Check out Mobile Tidings!</indication>

This document, a Service Indication, tells the WAP client to store the following:

  • A link to
  • With text “Check out Mobile Tidings!
  • This typically shows up in a “WAP Push Inbox” or sometimes in the “SMS Inbox
  • The link will show when it was created
  • It should automatically be removed after the expiry time mentioned

Well here is the AT command to send this particular SI document:

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WAP Push SMS encoding

This entry is part 8 of 17 in the series Sending out an SMS

As I started to explain in the last post, a WAP push consists of an XML document sent to the device over SMS. This is true but somewhat simplified.
The truth is that we send:

  • an WBXML encoded XML
  • over WSP (Wireless Session Protocol)
  • over WDP (Wireless Datagram Protocol)
  • over SMS

This is called an unconfirmed push.
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WAP Push over SMS

This entry is part 7 of 17 in the series Sending out an SMS

As you may understand, the data you can send via SMS is limited. It is limited because:

  • A single message can only hold 160 GSM-7 encoded characters
  • Even though messages can be combined in to bigger ones, the total size is still limited in several ways:
    • A message can have at most 256 parts
    • The receiving device as a (much lower) limit on how many parts it can reassemble into a bigger message
  • And if the technical limits aren’t prohibitive, the cost might be

So how do you send more and richer information to a device? There are 2 possibilities:

  • WAP push
  • MMS

Today I’ll focus on WAP push.

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