A telephone, is a telecommunications device that converts sound into electronic signals suitable for transmission via cables

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1answer
42 views

looking to capture an infared code

I am trying to get an infared signal being sent from an emitter (think along the lines of a remote control). I know I can use a fotoransistor on a breadboard to capture/detect the signal, but I have ...
0
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1answer
35 views

Patch-panel for phone splitter

I need a phone splitter (RJ11) to split 1 signal into 4 or more outputs. That's no problem, those can be bought in any store. But I was wondering if I can use a RJ45 cat6 patch-panel?
2
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2answers
61 views

Door phone audio signal to pc soundcard

I need to interface door phone system to a pc soundcard to listen and talk to the external unit. The door phone to interface is an as yc/200 of BPT and its a classic analog 4+n wires Door phone ...
0
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1answer
50 views

A voltage regulator that is controlling a voltage

My scenario is that I am having a circuit which having 12V as the input voltage and works beween 8V to 15V. I want to limit this circuit in a way that if the input voltage drops below 12V criuit ...
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1answer
67 views

Power a circuit and read output from tablet microphone port

I have a project that I'm currently powering with a AAA battery, providing 1.5v to a simple 555 timer circuit. The output of the circuit goes through a voltage divider into the microphone input of a ...
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2answers
115 views

Land line circuit suggestion / DTMF project

I am hoping to make a system that I can call in and using DTMF chip can control few things. I don't want to use a cell phone so it has to be a land line, however, it has to be automated so when the ...
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5answers
810 views

Control the hardware of an old phone using a Raspberry PI

I have a very old phone (60 years old) and I want to control its part using a Raspberry PI: Microphone & speaker from the head set The bell The dial wheel I have the electric circuit but don't ...
3
votes
1answer
108 views

telephone hold-on music

Can someone explain the following telephone hold-on music circuit in throughout manner because I am still learning how to simulate circuit using gnucap? When TR2 does not conduct, it switches off TR3 ...
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0answers
113 views

Using Java applet on a cheap Nokia phone to control Arduino via Bluetooth [closed]

I've built a nice wheel robot prototype with my kid. He had a broken R/C bigfoot truck: we've replaced its 'brains' with Arduino Pro Mini, DC motor drivers and HC-05 Bluetooth chip. Currently we ...
1
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2answers
59 views

Phone jack schematic and datasheet meaning

I am making an Eagle Cad library for this part, and I want to make sure I am making my part correctly. On this datasheet, http://www.switchcraft.com/Drawings/35rapc2av_cd.pdf, I am assuming that: ...
0
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1answer
112 views

Connecting phone using copper power wires

I want to install a video door phone (intercom) in my home, for this I have done a pre-wiring of 4 individual copper wires (normally used for home electricity) and the total length of wires is about ...
2
votes
2answers
240 views

POTS DAA circuit explanation

I am puzzling over this schematic, the datasheet just says to follow their recommendations exactly, and doesn't give explanation of the IC actions or circuit functions. The lower half is easy to ...
1
vote
1answer
36 views

Sampling phone line

I want to connect phone line to my PIC's ADC to sample signal changes without interfering the line. Human voice and DTMF signals are all under 4kHz level. So, I am hoping that any 18F PIC can do ...
0
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1answer
62 views

Connect 2 line phone to a 4 line system

There is a corporate phone system that uses multi-line phones. The idea is to connect a cheap 2 line phone only for answering calls without adding a line. Can this be done? Just connecting in ...
1
vote
3answers
119 views

Can a display landline phone instrument be made to work without a separate electrical connection

Since phone lines can supply power, there are landline phone instruments which work without a separate electrical connection. Typically these have no display etc. There are also those instruments ...
0
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2answers
79 views

What are these character sequences in connection with DTMF and a modem (telephony)?

I have a telephone, with which I dial a modem (analog, no ISDN) in order to send DTMF tones. If basically works, I receive something! For each key I press on the telephone I get a string like follows ...
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0answers
160 views

How can I isolate a short (in a mobile phone in this case)

I have a Nokia 6030 cell phone, and it's been serving me 7 years. It developed an interesting problem, which looks like a short of some kind: the battery drains very fast, for an hour or so, and the ...
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votes
1answer
401 views

Glitchy Touchscreen Caused by Charger [closed]

I recently bought a Nexus 4. I had a couple of spare chargers laying around. I used a charger that apparently had an issue exactly like: https://www.youtube.com/watch?v=mrpBTG0a6K8. If I used my own ...
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votes
2answers
122 views

Calculator with phone keypad question [closed]

I am not an electronic person and found this site in a my quest for the perfect calculator. I use both a phone and calculator for calculations and find the back and forth to cause me to make errors ...
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1answer
100 views

Powering cell phone from arduino

I am a beginner in electronics and I want to ask you a simple question. Can I power my old SE w200i directly from arduino, using resistive divider like this one: ...
3
votes
2answers
270 views

How to draw current from a telephone line?

My landline phone comes with a lcd display caller id and clock. Even if I remove the 2 AA 1.5V batteries, the lcd still shows time even if I'm not busy on a call. The lcd has no other source of power ...
3
votes
3answers
160 views

Why is speech malformed when listening to a USB signal with an LSB receiver?

When you listen to an LSB (Lower Side Band) signal with your radio set to USB (Upper Side Band) or vice versa, the speech you hear is malformed. What causes this behaviour?
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1answer
129 views

Piggybacking ethernet/phone on Cat5e?

I've got a phone line on the blue pair, and VDSL on the brown pair. Leaving the orange and green pairs available. But when I try and connect a router in one room, and a laptop in the other room, I ...
0
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0answers
102 views

Erlang B telecom system (grade of service)

I am bit stuck with an answered question that I found online: We have an Erlang B system where the total number of served call is 15.48 erlangs. The system contains 23 circuits. The incoming calls ...
11
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1answer
502 views

Could someone help me understand this simple circuit?

This is a single-wire earth-return telephone system used in cave rescue communications. simulate this circuit – Schematic created using CircuitLab The ground is a metal casing to make ...
6
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2answers
1k views

How does a signal travel down a telephone wire?

To get data to a computer the telephone wire must sent a signal but how does it do it ? Does it use analogue or a digital signal? How does it send the "1s" and "0s"?
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0answers
52 views

Mimic a condenser mic with a dynamic mic and a FET

I read all I could find here before posting, so far nothing is close enough to the question. Assume a dynamic mic, kind of like the one Radio Shack sells for old school tape players, and assume an ...
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1answer
134 views

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 ...
3
votes
1answer
698 views

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 ...
2
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4answers
7k views

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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1answer
77 views

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 ...
1
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2answers
143 views

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 ...
0
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0answers
282 views

Ring detector circuit, transistors not fully activating

I am attempting to build a ringer interface circuit, and I’m running into problems that are over my head. The purpose of the circuit is to buffer the output of a central telephone system that goes to ...
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1answer
1k views

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 ...
4
votes
1answer
1k views

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 ...
3
votes
1answer
259 views

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 ...
1
vote
2answers
108 views

Using a vintage US touchtone phone on a the Swiss ISDN network [closed]

I have one of these phones (US touchtone phone from the '70s): and would like to use it in my house in Switzerland where the phone system is ISDN. My electrician told me it can't be used here, but ...
0
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3answers
179 views

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 ...
1
vote
0answers
239 views

I am looking for a way to interface a phone landline with my computer's sound card in both directions [closed]

My approaches so far: This thread seems to go nowhere. It was trying to build the circuitry myself, but people have problems recommending suitable circuits. We keep on fiddling about with ...
2
votes
2answers
400 views

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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votes
1answer
757 views

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. ...
2
votes
2answers
685 views

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 ...
4
votes
2answers
380 views

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 ...
3
votes
2answers
647 views

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 ...
1
vote
1answer
290 views

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 ...
2
votes
2answers
569 views

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), ...
1
vote
0answers
163 views

how to wire 6p2c to 4p4c [closed]

I bought an adapter that will let me use a bluetooth headset with a landline telephone. Problem is, the connector my Cisco IP Phone 7960 series is expecting is a 4P4C, but the connectors on the ...
2
votes
1answer
300 views

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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votes
3answers
370 views

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 ...
6
votes
1answer
4k views

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 ...