Questions tagged [telephone]
A telephone, is a telecommunications device that converts sound into electronic signals suitable for transmission via cables
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How does a signal travel down a telephone wire?
Supposing a computer gets data over telephone wire, it has to send/recieve signals, but how do things work?
Does it use analog signal or a digital bits?
How does it send/recieve "1"s and "0"s?
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sniff telephone line data using old modem [closed]
i have an old modem that i'd like to use to sniff the data going out on the telephone line. i realize that i can't use the computers serial port to process the data as they are real slow. Can anyone ...
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Wiring a 1920s intercom to a contemporary door-entry phone
I have recently purchased a 1920s wall-mounted intercom:
I would like to connect this unit to our existing "4+n" door entry phone system, replacing the cheap plastic handset that we currently use (...
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How to create a multi-extension intercom system using wired phones?
I want to create a simple (telephone based) intercom system in our new house. Shouting between rooms is not so good, and trying to use an IM client or Facetime doesn't have the immediacy of a good ...
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Insertion loss and Envelope Delay
Following diagram shows characteristics of typical telephone connection. (Insertion loss and Envelope Delay respectively)
I have been able to understand, that plots are due to dispersive nature of ...
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Is telephone and LAN wiring symmetrical?
Is telephone and 10/100 MBps LAN wiring electrically symmetrical? I mean is it allowed to swap wires in the pairs, or is one of them like GND so they cannot be swapped? It's important to know when I ...
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Mobile/Cell Phone Power consumption?
I'm trying to work out the amount of watts my mobile phone uses and thus how much power it needs to charge back to full power. My handset is the Nokia 820 Lumia and the specs are as follows:
Battery 3....
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Answering landline calls with an Arduino
How can I connect an Arduino to a phone line such that, when a call rings, the Arduino will 'answer' and be able to respond with (touch) tones and, if possible, 'hear' touch tones as well for 2-way ...
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switch small DC voltage with 90v. 30hz AC signal
I need to momentarily activate an approx. 50mA @ 24V DC load, using a 90V, 30hz AC signal line. Whatever method is used, it needs to have the smallest current draw from the signal line possible.
I ...
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How to attach normal Phone handset to jack 3.5 [closed]
I have this Question :
How can I attach the normal phone handset to jack 3.5 to use with my cell phone?
For example : there is a product, http://www.cellphoneshop.net/redtel.html
Could someone give ...
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Humming and Transmission issues
First of all, I am going through designing all of this because I did not find a ready made circuitry for my purpose which is mentioned later. If you know a circuitry that is well tested and does what ...
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Connecting a telephone to the computer's soundcard to playback music samples while talking [duplicate]
Possible Duplicate:
How to boost audio volume coming from a telephone
Foreword: If you don't know the answer, don't leave. Write your idea where I could find an answer to this as a comment.
I ...
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ringer circuit old telephone
I am in the process of adapting an old phone to be used as an Bluetooth phone. I am currently testing the ringer circuit, which I build using the schematics provided by Sparkfun.
I wired up the stuff ...
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What electric part is on this manhole cover?
Here's a photo of a manhole cover
The letters form the word "ТЕЛЕФОН" ("telephone" in Russian in ALL CAPS).
What is on the picture in the center? Perhaps it is some part that should be associated ...
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What is the difference between a T-Carrier and a Digital Signal?
If you take a look at a digital transmission hierarchy for a telephone network or some data provider, you can see the terms T1, T2, T3 (Tx) and DS0, DS1, DS3 (DSx) used interchangeably.
Is there any ...
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How to mix High-Z and Low-Z audio signals? (Sum should be High-Z)
I'm trying to inject additional sound into a phone call. Therefore i modified a basic cable headset to use audio from my iPod.
This is my current prototype circuit:
That circuit is already working, ...
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GSM/GPRS module to call phone
I would like to do a DIY intrusion detection system.
I think I understand roughly what it's needed (door magnetic switches, windows magnetic switches, IR motion detection, password prompt, webcam), ...
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Analog Telephone Frequency Response Curve
Old analog telephone circuits using carbon microphones seem to be said to have a frequency response of, from various low frequencies which differing reports put at between 275 Hz and 400 Hz, up to ...
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Voltage Limit of CAT 5 DSL wire
I have been using threads(single wire) inside CAT 5e wire in a project for providing input to the circuit and output to a telephone. The source is 50V DC but the input to my circuit is just 4.86V DC ...
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How do I connect an Arduino to a landline?
How do I connect an Arduino to a landline telephone wall outlet?
I'm thinking of home automation, something like:
I call my house, and after a few rings the Arduino picks up the phone
The Arduino ...
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How do I implement "in" and "out" connections of this circuit on a breadboard?
I am implementing this circuit on a breadboard. The problem is I don't understand how to implement IN2 and OUT2 which is connected to 330PF capacitor, as input and output can't be insert in the same ...
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Building a telephone spy
I am implementing the following circuit
but I am stuck at one point.
How can we input the wires in IN1 , IN2, OUT1, OUT2? I don't know which wire to insert because there are almost 4 or 5 wires ...
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Cell Phone as Microcontroller
I have a couple of cell phones laying around, one of them being this one:
http://www.gsmarena.com/sony_ericsson_elm-3057.php
Is possible to clear the flash memory and replace it with a bootloader and ...
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How to build a telephone answering machine with caller ID [closed]
I'm brand new to electronics. I'm interested in building my own telephone answering machine with caller ID receiver from scratch as a learning project. How would you suggest I get started?
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Phone line to 3.5mm audio line
I need to splice out the audio feed from the hand set line (4P4C jack) to a 3.5mm audio port on a computer to interoperate the call via speech recognition. I do not meddle around too much with analog ...
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Why don't my rechargeable AAA batteries work in my cordless phone? [closed]
I'm trying to replace the AAA batteries that came with my BT cordless phone, as they are terrible quality and have quickly degraded (they now only last about 20 minutes after full charge). They are 1....
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I'm looking for a low-parts-count Arduino <-> phone & POTS line interface [closed]
[UPDATE - I found a partial solution here - http://www.joes.com/intercom/index.html - it's an intercom, not a full PBX.]
I'm looking for links to circuit design for an Arduino-controlled mini-PBX ...
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Hybrid phone echo cancellation circuit
I'm using a single board computer to talk on a phone line through two coils, one for the TX part, the other for the RX. The phone line is on another coil and then it's connected to a two-wire circuit ...
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How to use a DKO48 telephone microphone?
I have an old telephone made in the sixties (FF-OB/ZB or FF53). Now, I was planning to make an external speaker for that telephone, but I failed miserably, so I've put that aside.
Now, the handset ...
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Extending a pulse from a DTMF Decoder
I have built a DTMF decoder which offers relay closures corresponding to the digits received. Everything works great, except the equipment I am interfacing to is slow.
The office telephone system ...
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Commonly used standard for telephone wires
What type of wires are commonly used as indoor phone lines? I'm curious to know what is their bandwidth compared to my CAT5 cable that I use with DSL modem.
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Connect IPOD audio output to old rotary telephone
I hope you could help me. I want to connect the audio output of an IPOD to an old rotary telephone. The telephone is not connected to the telephone line, it's just a fancy design thing I would like to ...
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Testing a phone cable length
This story must be quite familiar:
From the start, I've had a problem with my phone/ADSL line: Cracks, hisses and other noise on the phone - enough to make it occasionally unusable, along with an ...
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Tool to test analog phone line connection quality
An ancillary job of mine is to support an analog phone line for our credit card machine. From time to time AT&T changes out hardware in the core which causes the machine's modem to not connect ...
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Using a telephone cable to power up a light blub
Is it possible for one to connect a telephone cable to light up a light-bulb?
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Negative effects of using underrated chargers
I was wondering what the effects of using a lower rating power rated supply for device would be. For example using a 1.52A supply at 19V to power a device where the charger that comes with the device ...
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How can I prevent incoming calls to two phones?
I am looking to build a small circuit board that would allow me to prevent incoming calls from reaching a device but still allow outgoing calls to reach their destination.
This is for a standard RJ11 ...
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Max current draw from a UK Phone Line?
Reading a question on SuperUser where someone received an electric shock from a modem made me curious, how much power can a phone line provide?
(I'm not looking to do anything dodgy like try to ...
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How can I locate items from a phone? RFID?
I'd like to be able to put something small on items (eg glasses, car keys, etc) and have an Android or iPhone app that will tell me the direction or proximity of a certain item. Current phones usually ...
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Is it just me, or is charging via usb not as good as using an outlet?
I used to charge my phone during the day at work with a USB cable (plugged into my workstation). Obviously USB doesn't provide the same amount of juice as an outlet so it took all day to charge but ...
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Why do PBX systems use -48 V?
It seems common that PBX and other telephone hardware use a positive-ground power supply, where the "hot" line is at -48v. What's the reason for that?
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Can anyone identify this phone PCB?
Can anyone identify this mobile phone?
http://www.adafruit.com/blog/2010/10/29/what-is-that-electronic-thing-from-yemen/
http://www.flickr.com/photos/ladyada/5126516011/
http://www.bunniestudios....
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Connecting two phone handsets to talk
I am hacking some old phones into my arduino project. I am currently controlling all of the ringers, dials, and hooks through my board.
At a certain point, I would like to connect the two handsets ...
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Wiring up old phone ringer to arduino
I just obtained an old rotary phone at a garage sale. I am working on hooking it up to an arduino project, and I was able to get the dial and hook switches figured out pretty easily. I cannot really ...
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Connecting landline to soundcard
I'd like to connect my landline tellephone to my computer's soudcard, and I was about to do this when somebody warned me that the voltages are all wrong and that I will blow my soundcard.
To what ...
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Telephone line acceptable path loss?
I'm trying to dig up the "rule of thumb" value for what a telephone company would consider acceptable path loss when they run a new line out to a customer. I spent a lot of time in digital telephony ...
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SIM card for SMS messaging application. Just pay per text (SMS) rather than monthly fee? [closed]
I"m working on an app that uses text messaging (SMS) in an embedded application and I'd like to source a SIM card where I just pay per text (dont really care about the rates) but I refuse to pay a ...
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