Overview of GSM/GPRS Modems

Introduction

A GSM modem is a wireless modem that works with GSM networks. A wireless modem behaves like a Hayes compatible dial-up modem. The main difference between a standard Hayes modem and a GSM modem is that a hayes modem sends and receives data through a fixed telephone line while a GSM modem sends and receives data through radio waves.

A GSM modem can be an external unit or a PCMCIA card (also called PC Card). An external GSM modem is connected to a PC through a serial cable, a USB cable, Bluetooth or Infrared. Like a GSM mobile phone, a GSM modem requires a SIM card from a wireless carrier in order to operate.

PC's use AT commands to control a modem. GSM modems and normal Hayes modems support a common set of AT commands. You can use a GSM modem just like a hayes compatible modem.
GSM modems support an extended set of AT commands. These extended AT commands are defined in the GSM standards. With the extended AT commands, you can do things like:

Read, write and delete SMS messages.
Send SMS messages.
Monitor the signal strength.
Monitor the charging status and charge level of the battery.
Read, write and searche phone book entries.

The number of SMS messages that can be processed by a GSM modem is pretty low, approx six messages per minute.

A GPRS modem is a GSM modem with additional support for GPRS technology for data transmission. GPRS means: 'General Packet Radio Service'. It is based on a packet-switched technology, as an extension to GSM (note thatGSM is a circuit-switched). An advantage of GPRS over GSM is that GPRS has a much higher data transmission speed.

GPRS can be used as the bearer of SMS. If SMS over GPRS is used, an SMS transmission speed of about 30 SMS messages per minute may be achieved. This is much faster than SMS over GSM. A GPRS modem is required to send and receive SMS via GPRS. Some wireless carriers do not support the sending and receiving of SMS via GPRS. A GPRS modem is typically required for MMS.

List of GSM/GPRS wireless modems

  Audiotel Industrial GSM/GPRS Modem »
  Audiotel Industrial RTU GSM/GPRS Modem »
  BluOcean GSM-S-A1/U1/W1 modems »
  BluOcean GSM-U-A1/U1/W1 modems »
  BluOcean USB GSM Modem Mini »
  BluOcean GPRS-U-A1/U1/W1 modems »
  BluOcean GPRS-S-A5/U5/W5 modems »
  BluOcean GPRS-S-A5/U5/W5 modems »
  ConiuGo GPRS GSM Dualband Modem »
  ConiuGo GPRS GSM Quadband Modem »
  Cinterio MC35iT Terminal »
  Cinterio TC65T Quad-Band Terminal »
  Cinterio TC35iT Terminal »
  Duxbury 120M USB EDGE Modem »
  Duxbury 120S GSM GPRS FAX Modem »
  Duxbury 180M USB EDGE Modem »
  Duxbury 180S EGSM DATA VOICE FAX Modem »
  Elpro GSM GPRS modem E605-M1 »
  Elpro GSM GPRS modem E605-M1 »
  Enfora Spider SA »
  Falcom Samba Dual Band GSM/GPRS Modem »
  Falcom Samba 3G UMTS/HSDPA Quad Band Modem »
  Falcom Samba 55/56 - Tri Band GSM/GPRS Modem »
  Falcom Samba 75 - Quad Band GSM/GPRS/EDGE Modem »
  Falcom Tango Dual Band GSM/GPRS Modem »
  Falcom Twist GSM/GPRS Modem »
  iTegno 3800 GPRS Modem »
  iTegno 3832 GPRS Modem »
  iTegno 3845 GPRS Modem »
  iTegno 3932 GPRS Modem »
  iTegno 3945 GPRS Modem »
  Multi-Tech MultiModem GPRS Wireless Modem »
  Multi-Tech MultiModem GPRS Wireless Modem »
  Moxa OnCell G2100 GSM/GPRS Modem »
  Multi-Tech MMCModem GPRS »
  NexWireless TMF622 USB Modem »
  Siemens ES75 EDGE GSM Modem »
  Novatel Expedite E725 PCI Express Mini Card »
  Novatel Expedite E760 PCI Express Mini Card »
  Novatel Expedite EU850D PCI Express Mini Card »
  Novatel Expedite EU870D PCI Express Mini Card »
  Novatel Merlin CC760 ComboCard Modem »
  Novatel Merlin X720 3G ExpressCard »
  Novatel Merlin X950D ExpressCard »
  Novatel Merlin XU870 3G ExpressCard »
  Novatel Merlin XV620 3G ExpressCard »
  Novatel Ovation MC727 USB Modem »
  Novatel Ovation MC930D Compact HSPA USB Modem »
  Novatel Ovation MC935D Compact HSPA USB Modem »
  Novatel Ovation MC950D HSDPA HSUPA UMTS USB Modem »
  Novatel Ovation MC990D Compact HSPA USB Modem »
  Option GTM380 Express MiniCard »
  Option GlobeTrotter Express 441 »
  Option GlobeTrotter Express 442 »
  Option GlobeTrotter Express HSUPA »
  Option GlobeTrotter GT MAX HSUPA »
  Option GTM382 MiniCard module »
  Option GTM501 wireless module »
  Option iCON 031 USB Device »
  Option iCON 210 USB Modem »
  Option iCON 225 HSDPA USB modem »
  Option iCON 315 USB modem »
  Option iCON 322 USB Device »
  Option iCON 401 USB Device »
  Option iCON 431 USB Device »
  Option iCON 451 USB Device »
  Option iCON 452 USB Device »
  Option iCON 505 USB Device »
  Option Gobi 1000 »
  Option Gobi 2000 »
  Rutronik GS64 Terminal »
  Rutronik GT64 Terminal »
  Rutronik GT863-PY Terminal »
  Rutronik GT864 Terminal »
  Rutronik UT864 UMTS Terminal »
  Siemens M20 Terminal »
  Siemens MTC45MC and MTC45TC Terminal »
  Siemens TC35 Terminal »
  Siemens TC65 GSM Modem »
  Teltonika Handheld GPS GSM Tracker GH1201 »
  Teltonika Handheld GPS GSM Tracker GH1202 »
  Telit GT863-PY terminal »
  Telit GT864-QUAD-PY terminal »
  Teltonika ModemUSB G10 »
  Teltonika ModemCOM G10 »
  Teltonika ModemPCI G10 »
  WaveCom Fastrack GO »
  WaveCom Fastrack M1306B GSM Modem »
  WaveCom Fastrack Supreme »
  WaveCom Fastrack Xtend »
  WaveCom Integra M2106B GSM Modem »
  WaveCom Integra M2106+ »
  WaveCom m-track 25 »