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SMS Costs.

Funny (or not so funny…) cost analysis follows:

“The maximum size for a text message is 160 characters, which takes 140 bytes because there are only 7 bits per character in the text messaging system, and we assume the average price for a text message is 5p. There are 1,048,576 bytes in a megabyte, so that’s 1 million/140 = 7490 text messages to transmit one megabyte. At 5p each, that’s £374.49 per MB - or about 4.4 times more expensive than the ‘most pessimistic’ estimate for Hubble Space Telescope transmission costs.”

More here.

2008 05 14 Thanasis General Comments (0) Permalink

Information for SMSLib v3.3 (JDK5).

Since many of you have reported problems and deadlocks using the asynchronous feature of SMSLib, I thought about changing the logic a bit:

Currently, what you get back from an inbound notification is a Memory Storage/Location combination. Using those, you should call SMSLib and read whatever message is stored at the specific memory. Two bad things happen here:

  • Many of you reported deadlocks.
  • You cannot process large (multipart) messages - since a separate notification arrives for each part of the message.

The new SMSLib frees you of that load: it handles all raw notifications internally, reconstructs messages and calls you with a real message (and not a memory storage/location parameters). I hope this will make our lives easier.

Those of you who wish to try this out, feel free to check out the code from the Subversion branch here:

http://smslib.googlecode.com/svn/smslib/branches/v3.3.0-jdk5/

We are still moving code around and modify it according to JDK5, but I think its a workable copy - at least we try to commit code that is working fine.

2008 05 11 Thanasis General Comments (0) Permalink

Voipbuster integration(?)

I was thinking of making an HTTP handler for Voipbuster, so as to give the capability to sent messages via Voipbuster services. Their fees are quite low. I went on and registered, paid my initial fee and started to play around with HTTP posts and caller ids.

I have encountered a problem though…

I have 2-3 test phones available. For the newer models, everything worked ok. On the older model (Nokia 6310i) I couldn’t manage to get my CALLERID displayed properly for messages sent via Voipbuster. The worst of all is that for this phone (the old model), Voipbuster returned delivery errors, although the message is eventually received (and charged for)…

I’ve searched their forum and found several complains about their SMS services. I was also interested in finding documentation on the HTTP response codes, but found nothing. The HTTP responses are a bit cryptic, consisting of two numbers (resembling a major and minor error code) and a text error message (probably a description).

As it stands I am afraid I cannot publish a Voipbuster gateway, as it would create more confusion than good. Imagine failed messages being delivered and charged!

Any ideas? Should I just skip it? Or publish it with a big warning?

2008 05 10 Thanasis General Comments (0) Permalink

SMSLib forum.

After solving the problems with the previous attempt of activating a forum (it was actually a hosting problem, not an application problem), SMSLib forum is available again at http://smslib.org/forum

Unfortunatelly, those few posts and registrations made on the old forum are gone…I’ve switched from SimpleMachines to PunBB, as it is more lightweight.

After a few days (if everything goes well) the mailing list will probably be set to read-only mode (for archival purposes). If you face any problems, let me know either here or at the dedicated thread: http://smslib.org/forum/viewtopic.php?id=3

2008 05 03 Thanasis General Comments (0) Permalink