There are different ways to send or to receive a SMS. The simplest with a GSM modem. Unfortunately, a GSM-Modem can process only 6 to 10 SMS per minute. To increase the speed a connect to a communication server with up to 32 GSM modem is neccesary. Then becomes possible with it up to 320 SMS per minute. With this kind of SMS communication none direct connect to SMSC is necessary. Some GSM operators offer no direct connect. Consequently, the communication server with 32 GSM modem is a good alternative.
Faster and more comfortable is the direct link to the SMSC. With a direct acces you can reach up to 600 SMS per minute. Popular protocols are UCP, SMPP, CIMD2, OIS and TAP. TAP is an old protocol to the send messages to a
pager. Causes historically, TAP offers sent of messages from server only.
With which hardware the SMSC can be connected is not the same by all the different operators. The exact data must be asked at the GSM operator. The parameters are not equal also. Through the variety, the likelihood of a mistake is very large.
For the world wide market, there is a big number of software to ease the direct access to SMSC. The offer is from Freeware, Open Sources up to software which almost all types of the communications masters.
With Freeware, there is usually no support. The protocols named above are developed further continually. So constantly changes on the software is necessary.
The following graphics shows an example for a software which at many companies in the usage. Many settings of GSM operators already in the default parameters. Further new operators are added by the developer usually free of charge. The functions of the software and service / support is perfect.Whoever nevertheless thinks to save money with own drivers finds the sources of the known protocols in the appendix. There are still students, which must develop drivers itself.
List of SMSC protocols you will fink if you follow the button LINKS on the top menue.