I think you're going to find mixed answers on this. Personally, I prefer using a provider for a few reasons:
1) Short codes are possible
2) You can typically send out a greater quantity and a more rapid rate
3) You may have access to networks and providers you may not have otherwise from your GSM provider.
However, if you're doing a small operation or just playing around with
Kannel and SMS, then using a GSM modem or a GSM phone modem will
probably be the best answer since most providers require a minimum to
use their SMPP services and you may already have a GSM phone.
Like almost anything else, it depends on what exactly you want to do..
I'm currently using a SMS provider for sending all of the messages that our system requires... But I'm looking towards bringing that in house, due
to several issues we've had..
I've subscribed to the list, and have been reading it for a few weeks now, in order to get a general idea of the layout, before I begin planning a change..
My question is this.. (I'm in the US, and so are the majority of the
phones we send messages to, if that matters).. For sending messages, are you (Most people) using a SIM card that you have from a mobile provider for sending the message.. That is, are you getting a phone contract with
someone, taking their SIM card, and plugging it into your GSM modem?
Or are you working out a contract deal with a provider, specifically for sending messages?