Questions tagged [modem]
A modem (modulator-demodulator) is a device used to transmit and receive digital data over an analog communications channel. Common examples are PC modems that use an analog telephone line and wireless modems that use RF (radio frequency).
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Managing Power and Sleep in a BK 7600G from AND-technologies
I work with a BK-7600G board that has a SIMCOM7600G.Documentation of the manufacturer (AND-technologies) seems to me limited.
A. Regarding power on and power off:
Using the POWERKEY
We see in the ...
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Modem RC7611 cannot connect in the ATT carrier
I have a problem with the GPRS modem RC7611 of Sierra Wireless, it initialize correctly, finding the sim card and respond the AT commands, but when it will connect in the carrier, it receive a denied ...
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STM32 Over-The-Air update with SIM7682E LTE modem
I have a need to add an Over-The-Air firmware update feature to my project. It is based on STM32F103CBT6 and SIMCOM SIM7682E LTE modem.
The main idea is to connect to the FTP server or get the file ...
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GSM and LTE-M connection with SIM7070G for MQTT data transmission
I am working on a tracker project using the SIM7070G modem from SIMCOM. The objective is to maximize the connection by working with both LTE-M and GSM, aiming to send location data via MQTT.
I have ...
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Help me identify this unknown SMD transistor
Could you help me identify this transistor?
I have searched every SMD code decoder and can't find the exact type of this transistor:
It apparently has CCE1X written on it, and has a SOT-23-6 package ...
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Data logging on a SIM5320
One of my SIM5320 devices is using a lot more data than before while sending a POST message to a web server. I like to see what connections the SIM5320 is establishing, but i don't know how. What is ...
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How to access modem inside Android mobile from a PC through USB cable? [closed]
Every mobile has a modem inside it, which allows dialing phone numbers and connecting to data/GPRS.
I guess we can send AT commands to all modems in phones.
So if I tear down an Android phone e.g. a ...
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Problem with GPS old location [closed]
I wrote a GPS driver which sends and reads AT commands. I send the AT+CGPS=1,1 command to get the GPS location and if there is no answer I send ...
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Sizing the DC/DC inductor for only momentary high currents
My DC/DC setup is going to power a GSM modem. The behavior of these modems is that they typically consume only a few tens of milliamps, but when transmitting they are drawing 2A for microseconds. On ...
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SIM7080 UART Noise interfacing with PIC18F4550
I'm working on a project where I read data over Modbus line and send it in the cloud service through a SIM7080 CATM modem. I'm using PIC18F4550 as MCU.
As that PIC18F has just one UART module, I'm ...
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Two devices sharing the same coaxial cable, what frequency channel should I chose? [closed]
The 2-stories house is equipped with a coaxial cable that has wall plugs in 1st and 2nd floors (it's also connected to the antenna on the roof).
Our IAP installed a modem for Internet (Arris CM820C) ...
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FTDI cable (TTL-232R-3V3) mixed up wires [closed]
At the beginning of the measuring task, I mixed up wires connecting my FTDI USB to UART cable (TTL-232R-3V3) with serial connector header pins (TX/RX/VCC/Gnd) on device (data modem). I didn't ...
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Jumps in signal/noise ratio on problematic VDSL connection
(I am not sure this question is on-topic here. It seemed off-topic in networking because the connection is not in a professionally managed environment. Perhaps super user would be a better fit? But ...
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Problem with using power bank for modem with dc dc booster
I want to run a modem that needs 12 volts with a power bank.
I've used a DC-DC booster to increase the voltage of my power bank which is 5 volts up to 12 volts and there is no problem with that.
After ...
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Providing phone line current for direct modem-modem communication
In order to directly connect two modems without a real phone line, one option is to put a battery inline (to create the current loop?). Most information I've found about this relates to the SEGA ...
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Could power cycling a modem 24 times a day for over 3 years (>30,000 times) cause the modem to lose its settings? [closed]
Could power cycling a modem 24 times a day with it being on for 10mins at a time for over 3 years (>30,000 times) cause the modem to lose its setting and revert to factory?
This modem.
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What connector is this? (Inside a wifi modem)
I was about to attach an antenna to my 4g modem and thus trying to identify which connector is there on my modem board and i found this connector (4 of them, 2 for 4g and 2 for wifi).
I tried ...
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A few questions on modem/AT commands
A couple of questions about modem:
I have been reading up on AT commands, and I see they're used to control the modem. They are sent over a serial connection so does that mean they are sent over UART?...
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Relay not switching immediately if mains off to battery like UPS
Relay not switching immediately if mains off to battery like as backup power. I'm looking for zero cross SPDT relay switching for my project. please help. design is simple two power sources (mains and ...
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Do DSL / ADSL modems have an ADC with ~ 2 MHz sampling rate?
For fun and no real practical use, I'm trying to design a DIY modem that can transmit data over an audio line, like old 56k modems did. I'm studying how to pack bits of data efficiently in a 1k-15k ...
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SIM7600 HTTP post 204
Using stm32L451 with a Sim7600.
I am trying to post data to a Ubitdots dashboard using HTTP post and the response is 204 which means no data is load but a connection was made to the server, I have ...
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Boot failure in wifi module
I am using a redpine rs9113 WiFi module in my device functioning with stm32l476 micro controller. Spi is used for the communication with the modem. While communicating with the modem, it constantly ...
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Wireless internet signal bi-directional amplification?
So I have little to nothing experience with anything wireless related. the WiFi modem I have in my house is far from my room and the signal is weak, so it reduces the communication rate. my first ...
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Is it possible to use SIM7600 modem for both data and SMS simultaneously?
I am interested in using the SIM7600 module for designing a system with LTE communication. The module will be connected to the host system via USB.
I would like the host system's Linux to use PPP to ...
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SIM7000E modem stops sending SEND OK reply
I am using a SIMCOM SIM7000E modem to send data using MQTT. Usually modem reply correctly to
AT+CIPSEND command and sent ">" to enter the required data and then reply with "SEND OK&...
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SIM868 powers down after few seconds
I designed a circuit with SIM868 module, and i followed the recommendation from datasheet to unsure suffusion current.
The main power supply is getting from VCC:12V source converted to 5V by an DC-DC ...
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OpenOCD throws "JTAG scan chain interrogation failed: all zeroes" error
I am trying to install openWRT on a router using my Raspberry Pi Zero. I am following the exact steps as explained in http://www.alfredklomp.com/technology/experia-v8/
However, for some reason I keep ...
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Are Fiber Media Converters Technically Modems? [closed]
Fiber media converters are devices used to convert fiber optic signals to other types of (digital) network data.
I'm curious as to whether these devices technically fit the definition of a Modem? If ...
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Accessing SMT pins on prototype board
I need to be able to solder wires to the hidden pins of an smt ic. The ic is soldered directly to the pcb, and they are not visible. I need to access the PCM audio interface on a sim7500e, and the ...
user240198
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Why download and upload speed is different in 56k modems?
I have read that this is due to the absence of an A/D or D/A conversion (only) in the down stream which would normally introduce some quantization error. This conversion is present in the upload, so ...
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TCP data vs HTTP data over GSM modem
I am using M95 GSM Modem for remote data communication with the server. The server-end persons want me to use HTTP data connection.
Another embedded guy has suggested to use sockets and TCP data for ...
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Long term health effects of a gsm modem [closed]
We all use internet through our mobile phones hence gsm infrastructure. I know the radiation exposure is higher than wifi. That's why I preffer wifi over mobile whereever i can.
However I'm currently ...
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How are MBIM transaction ID's supposed to be used?
Situation
I am developing a product that will use this Sierra Wireless HL7618RD Cat 1 LTE modem. I am interfacing to the modem over USB using a small SoM running a Debian flavor of Linux. The modem is ...
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Phone on a breadbord
My current electronics project is to build a very simple customizable "phone". It is my own idea, with as ultimate goal to learn about microcontrollers and basic electronics.
This is my set-up so far
...
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Problem with 2G Modem's supply power
I want to run a 2G Modem HL6528RD. I provide it with 3.6 V, got from the following circuit :
I finally manage to make it work but the problem is that if R108 is mounted, the modem doesn’t work, (the ...
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Audio filtering circuit with capacitor shorted
I was looking at the Adafruit FONA cellular network modem breakout board schematic and found something that I can't quite understand. The breakout board has an audio input and output that both goes ...
user109388
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(When) Can I use Cat5e wiring to carry a POTS signal to a DSL modem?
According to this answer by @asndre,
It is very bad idea to use Cat5e-based wiring/cabling to establish a
xDSL connection.
However, my telephone/internet provider technician recommended -- and ...
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Confusion between analog & digital signal and modem
Telephone wire is a lowpass chaneel so the process looks like below. (Maybe right?)
Voice(analog signal) → Sampling(digial data) → Coding(digial signal) → transmit
There's no need to convert digital ...
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Would it be energy efficient for phones to include actual GPS chip? [closed]
None of the smartphones today have dedicated GPS chips in them, they only have a GPS capability that stems from byproduct features of the modem chips. Because of that, the GPS capability is very ...
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Force cellular modem to transmit at maximum power [duplicate]
I want to force my cellular modem to transmit at maximum power so that I can see if that is the cause of microSD card crashes that I have been experiencing in an embedded application.
My modem is a ...
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MoCa - Ethernet over Coaxial
This is specifically a high-level hobbyist question, I'm not really looking for schematics or anything of the sort.
To deliver Ethernet over Coaxial, what sort of high-level designs or common issues ...
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How does things work between MODEM and PC on the RJ45 ethernet cable? [closed]
I am a newbie in electronic and i would like to ask why there is Transmitter and Receiver in the RJ45 cable connecting the MODEM and Computer? Which one goes first
From Modem --> Receiver Receive ...
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How did dial-up modems make noise when initializing internet connection
A 56k modem sounded like this. I read somewhere that the reason for these whistles and chirps and buzzes is to give the user the feedback that something was happening during the handshake.
I guess ...
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Dialup Modem To Generate Musical Tones [closed]
Just brainstorming here but would it be possible to control the actual audio band signals emitted by a modem like an old US Robotics V.90 or similar? I'm guessing not without somehow rewriting the ...
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Is this warning about wireless modules interfering with aircraft systems true?
I see the following warning for Sierra wireless (cellular) modems:
Do not operate the Sierra Wireless modem in any aircraft, whether the aircraft is on the ground or in flight. In aircraft, the ...
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Superimpose a High Frequency AC Small Signal on a DC Power Signal
I am facing a challenging problem with a circuit that I am currently working on, I would like others input and thoughts.
I have a DC power signal that I am injecting a AC small signal this mixed ...
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SIM7100 GSM Modem Unreliable Connection
I am trying to communicate with SIM7100 GSM modem but I could just rarely communicate with it across UART interface. I am observing the signal with an oscilloscope, I am giving 5V as High and 0V as ...
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Isolate UART Signal Pins
I'm working with an embedded cell modem that will be living on a battery, hopefully for a long period. It only wakes up and sends data occasionally. To that end, my plan is to cut power to it when ...
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What is effect of echo canceller on QAM signals?
During data call or fax call echo cancellers are switched off in entire path from phone to exchange and exchange to phone.
Echo canceller are used to cancel echo during voice call. Modulation in data ...
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Usb 3G, 4G modems, power supply
I have read that usually a gsm module requires a power supply capable to provide up to 2A. But how can 3g modems sticks work properly when they are powered through usb port which provides only up to ...
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