Introduction to GSM Modem

A GSM Modem is a telecommunication device,
a wireless modem, that
uses GSM wireless network. GSM Modem comes in various interfaces,
such as PCMCIA Type II, USB, and Serial.

GSM Modem is similar with a 56k dial-up
modem (using telephone line), that it transmits and receives
data, or voice. However the main difference is that GSM Modem
is wireless, while dial-up modem is wired.

Some GSM Modems also has GPRS feature
that allows tramission of data over TCP/IP (internet).

To transmit data using GSM Modem, there
are various methods that can be used, such as:

SMS

CSD or HSCSD

GPRS

Even though a normal mobile phone can be used
as GSM Modem, it is higly recommended that a special
industrial grade terminal to be used as a GSM Modem due
to its stabilty, and reliability.

Answer: All GSM Modems support all type of SIM cards - prepaid or postpaid. However, please avoid using 3G SIM card or 128k SIM card. As it has compatibility problem with Wavecom GSM modems. If you have no choice and must use 128k SIM card, then DO NOT activate 3G service.