Electrical Engineering Stack Exchange
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Questions tagged [gsm]

GSM stands for Groupe Spécial Mobile. It is a standard set developed by the European Telecommunications Standards Institute (ETSI) to describe protocols for second generation (2G) digital cellular networks used by mobile phones.

GSM originally stood for Groupe Spécial Mobile, but since it went global, is often referred to as Global System for Mobile telecommunications. It is a standard set developed by the European Telecommunications Standards Institute (ETSI) to describe protocols for second generation (2G) digital cellular networks used by mobile phones.

Use this tag for questions related to any aspect of GSM systems.

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Why does GSM cause speakers to buzz?

Based on numerous internet resources, speaker wire acts like an antenna which picks up the transmitted signal of nearby cellphones and causes the speakers to buzz. But I'm not really buying that... A 3.5 mm speaker cable is designed to carry 1 V.…
JSideris
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Is an omnidirectional antenna a must for a cell phone?

I have read somewhere (but unfortunately I am not able to remember where) that cell phones do need an omnidirectional antenna. If it is so, what are the reasons for that? Why a normal directional loop antenna could not be (efficiently) used ?
Standard Sandun
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Dual-SIM phone, do they use 2 GSM modules ? Anyone has high level schematic?

As an slight extension of my project, I am trying to see if I can improve connectivity resilence by using a dual-SIM approach. Dual-SIM phones (or Tri-SIM, quad-SIM phones) are quite popular in many developing countries, and AFAIK, most are based on…
bdutta74
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Designing a GSM PCB antenna

Before someone complains about my crappy design I should tell you that my knowledge on antennas or RF is near zero. I recently worked on a project that required a GSM module. After testing it on a PCB using an external antenna that apparently seamed…
Bruno Ferreira
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What AT command should be sent to modem to get time?

I am using SIM800E. I want to know what AT command should be sent to the modem to get time? This modem has a RTC. But I need to set it automatically through cell tower. The tower can send the time to the modem when requested using an AT command. I…
gpuguy
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Simulate bad cell phone reception in the lab

I'm currently developing an internet of things device that utilizes a uBlox SARA-U260 gsm/3G modem. In field testing, we have had significant software/firmware issues due to poor cell phone reception in our deployments in sub-saharan Africa. I'm…
macdonaldtomw
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AT Commands to transmit data through TCP/IP stack with LTE network

I need to design an embedded sotfware that will drive a LTE cellular device (like u-Blox TOBY L2 Series) and its TCP/IP stack to transmit some data toward a distant server. I'm waiting for the device to be delivered at work. For now, I use a GPRS…
Bikemat
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Longest range remote control

I would like to make a long range (5Km) quadcopter. As of right now, I'm just trying to find out the best way to control it. I know that there are some 5Km R/C transmitters but they are the size of brick which is a little inconvenient. I was…
Riley Lloyd
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Can I remove a GSM module from an old cell phone?

I found this project that uses a GSM module (scroll down to see Picture 5). It seems the module has to be bought separately. I have old GSM cell phones lying around in the house. Shouldn't these phones contain such a chip? Is it possible to remove…
sauparna
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Why do cell phones sometimes interfere with amplifiers

I have an old Sony amplifier (TA-F117R) next to my desk where I keep my cell phone. Sometimes I put it ontop the amplifier, because it is pervecly alighed with the surface. When I hang some call up and land the phone close to the amplifier the loud…
Crowley
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How to properly power sim800l module?

I have this sim800L module It has a 3.7v - 4.2v voltage requirement. So I created a simple buck regulator using MIC4576 regulator according to it's schematics and adjusted it's output to 4.2 volts. It can provide 3A of current. And i powered it…
Suraj Bhawal
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Killing GSM Buzz with Ferrite Beads

I'm trying to rid my speakers of the typical buzz from my iPhone. I get poor reception in my apartment and so it's constantly trying to find a signal, meaning I get a near-constant buzzing when the phone's anywhere near it. Airplane Mode works, but…
Luke
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Typical GSM current profile

I'm working with GSM modem and I'm wondering if anyone has come across any sort of measured or typical GSM current profiles for various actions such as: Connecting to base station Sending a SMS Voice call During an active data connection I know…
Joel B
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Wavelengths blocked by a certain metal mesh

Introduction: I've heard about a theory, according to which you can check if there is any leakage in your microwave oven by putting your mobile phone inside and call it. However, I gave it a try and the call was successful. I realized that the two…
hryghr
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What's this noise?

As in other years at precisely this time I'm experiencing an effect somewhat like GSM frame-rate audio breakthrough in my auditory systems - completely different frequencies but equally wideband. I've noticed it occasionally in the past - always at…
Russell McMahon
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