SD SMS Master is an SMS-sending server.
The Web server (master) contains the SMS Master itself.
Clients (users) connect to the master and create orders.
Orders contain a text to send and a list of numbers to send to.
The master then connects to remote machines (slaves) and distributes the order numbers (+text)
to all enabled phones on the slaves.
The communication is one-way; incoming SMSes are not read.
