KalSMS VS mobile-gateway

I built one, way back (I'm not an Android dev, kind of hacked it together but on the positive side it's extremely simple: https://github.com/niryariv/KalSMS )

At the time there were a lot of developing countries projects using SMS as their main interface (a lot of work with community health workers etc). Orgs like the UN would set up an SMS gateway by hooking a desktop with some hardware, and of course it would be very vulnerable to stuff like power outages, someone tripping over the wires etc and you had to get the technician to set it up again. With smartphones you had the all the required setup in one cheap, small and very durable package, no training required to operate.

Standard SMS plans usually have a human-typing-in-a-keyboard rate limit, around a handful per minute - you can manually try this, I've got blocked a couple of times by spamming a friend with "a", "b", "c"...

Were I work, we've implemented a couple of nation-wide general population surveys regarding non-communicable diseases (working with those countries health authorities, of course). For the actual surveys, we get SMPP contracts with the local telcos because of this limit (and to get a vanity shortcode, reverse billing...).

We started thinking it would also be cheaper, too (due to the scale pricing) - but the human time required for working out contracts with developing-world telcos for a project involving state actors can easily counter that.

The throttling is something we need to take into account for the tiny-scale pre-tests we ran (while working out the contract) using an SMS Gateway App[0] we've built, similar to the one from this thread. The main difference is ours uses a queue-based protocol to exchange messages with a controlling server.

[0] https://github.com/instedd/mobile-gateway