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Andy Neil
11/08/05 17:15
Read: 1375 times

Msg Score: +1
 +1 Informative
#103449 - Glossary
Responding to: Craig Steiner's previous message
Craig Steiner said:
You can transmit data wirelessly over a GSM network by using a GPRS modem

You can also make data calls over GSM without the need for GPRS:

GSM Originally stood for "Group Special Mobile" - being the name of the ETSI committee that defined the specs.
Once the specs were done, it seemed silly to be still calling them after a committee, so they re-branded it as "Global System for Mobile communication" - which is pretty accurate and descriptive.
You can download all the specs for free from:

GSM is the Digital Cellular ("mobile phone") standard used in Europe and many other parts of the world.
In addition to voice calls, GSM supports many other services including Circuit-Switched Data, Fax, SMS (Text Messaging), etc.

Many manufacturers produce GSM "modems" which can be used in very much the same way as a normal land-line modem - with an RS232 interface, AT Commands, etc, etc.
Top names include Siemens, Sony-Ericsson, Wavecom, Falcom, Multitech, et al
You can also buy "modules" that contain just the "guts" of the modem on a "naked" board for embedding into other products - these would usually lack such things as enclosures, power supplies, RS232 transceivers, SIM holders, standard connectors, etc, etc. They may also require additional type-approval work.

GPRS is the General Packet Radio Service - it builds on the underlying GSM infrastructure to provide IP-based (packet) data services.
Use of GPRS requires an IP protocol stack.
Again, many manufacturers produce GPRS "modems" - some of which have TCP/IP built-in.
(in fact, you'd find it hard to find a current GSM "modem" today that didn't support GPRS!)

CDMA is Code-Division Multiple Access, which is a technique used in a number of communications applications. In this context, you are presumably thinking of the system championed by Qualcomm as an alternative to GSM.

DTMF is Dual-Tone, Multi-Frequency and has nothing specifically to do with wireless communications at all!
It was developed as a technique for in-band signalling (look it up) in wired telephone systems - also known as "Touch-Tone"
You should not attempt to send DTMF through a GSM phone link! (the GSM audio processing messes it up).

Suresh Kumar Kavula said:
would like to know how to interface these peripherals to 8 bit uC's.

Buy a modem.
Get it working with a modem, then move on to a module if required.

Use the Search facility on this site, as it has all been discussed plenty before already...

List of 13 messages in thread
GSM, GPRS, CDMA, DTMF wireless      Suresh Kumar Kavula      11/08/05 14:05      
   Google is your friend      Craig Steiner      11/08/05 14:20      
      Glossary        Andy Neil      11/08/05 17:15      
         you missed TDMA      Erik Malund      11/09/05 06:41      
            GSM is TDMA      Andy Neil      11/09/05 14:30      
               +FDMA      Dan Henry      11/09/05 17:11      
   CDPD, Wireless N/W parameters?      Suresh Kumar Kavula      11/09/05 10:57      
      Good luck, you will need it      Erik Malund      11/09/05 11:24      
      M2M      Andy Neil      11/09/05 14:41      
      Doesn't run on AT commands?      Andy Neil      11/09/05 14:43      
      CDPD - Obsolete?      Andy Neil      11/09/05 14:47      
         Valuable Info      Suresh Kumar Kavula      11/10/05 12:11      
      Data transfer direction/speed        Craig Steiner      11/10/05 12:30      

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