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The keypad PCB require extensive modification, seperating the existing button signals from the circuit.
The telephone, or phone was developed in 1876 by Alexander Graham Bell. and improved by many other inventors. Telephones rapidly became common in advanced societies.
The essential elements of a telephone are a microphone (transmitter) to speak into and an earphone (receiver) which reproduces the voice in a distant location. In addition, most telephones contain a ringer which produces a sound to announce an incoming telephone call, and a dial or keypad used to enter a telephone number when initiating a call to another telephone. Until approximately the 1970s most telephones used a rotary dial, which was superseded by the modern DTMF push-button dial, first introduced to the public by AT&T in 1963. The receiver and transmitter are usually built into a handset which is held up to the ear and mouth during conversation. The dial may be located either on the handset, or on a base unit to which the handset is connected. The transmitter converts the sound waves to electrical signals which are sent through the telephone network to the receiving phone. The receiving telephone converts the signals into audible sound in the receiver, or sometimes a loudspeaker. Telephones permit duplex communication, meaning they allow the people on both ends to talk simultaneously.
The first telephones were directly connected to each other from one customer's office or residence to another customer's location. Being impractical beyond just a few customers, these systems were quickly replaced by manually operated centrally located switchboards. This gave rise to landline telephone service in which each telephone is connected by a pair of dedicated wires to a local central office switching system, which developed into fully automated systems starting in the early 1900s. For greater mobility, various radio systems were developed for transmission between mobile customer stations on ships and automobiles from the 1930s by the mid-1900s. The first hand-held mobile phone was introduced for personal service starting in 1973 by Motorola. By the late 1970s several mobile telephone networks operated around the world. In 1983, the Advanced Mobile Phone System (AMPS) was launched in the U.S. and in other countries soon after, and offered a standardized technology providing portability for users within a region far beyond the personal residence or office location. These analog cellular system evolved into digital networks with better security, greater capacity, better regional coverage, and lower cost. The public switched telephone network, with its hierarchical system of many switching centers, interconnects telephones around the world for communication with each other. With the standardized international numbering system, E.164, each telephone line has an identifying telephone number, that may be called from any authorized telephone on the network.
Although originally designed for simple voice communications, convergence has enabled most modern cell phones to have many additional capabilities. They may be able to record spoken messages, send and receive text messages, take and display photographs or video, play music or games, surf the Internet, do road navigation or immerse the user in virtual reality. Since 1999, the trend for mobile phones is smartphones that integrate all mobile communication and computing needs.
BASIC PRINCIPLES
A traditional landline telephone system, also known as plain old telephone service (POTS), commonly carries both control and audio signals on the same twisted pair (C in diagram) of insulated wires, the telephone line. The control and signaling equipment consists of three components, the ringer, the hookswitch, and a dial. The ringer, or beeper, light or other device (A7), alerts the user to incoming calls. The hookswitch signals to the central office that the user has picked up the handset to either answer a call or initiate a call. A dial, if present, is used by the subscriber to transmit a telephone number to the central office when initiating a call. Until the 1960s dials used almost exclusively the rotary technology, which was replaced by dual-tone multi-frequency signaling (DTMF) with pushbutton telephones (A4).
A major expense of wire-line telephone service is the outside wire plant. Telephones transmit both the incoming and outgoing speech signals on a single pair of wires. A twisted pair line rejects electromagnetic interference (EMI) and crosstalk better than a single wire or an untwisted pair. The strong outgoing speech signal from the microphone (transmitter) does not overpower the weaker incoming speaker (receiver) signal with sidetone because a hybrid coil (A3) and other components compensate the imbalance. The junction box (B) arrests lightning (B2) and adjusts the line's resistance (B1) to maximize the signal power for the line length. Telephones have similar adjustments for inside line lengths (A8). The line voltages are negative compared to earth, to reduce galvanic corrosion. Negative voltage attracts positive metal ions toward the wires.
DETAILS OF OPERATION
The landline telephone contains a switchhook (A4) and an alerting device, usually a ringer (A7), that remains connected to the phone line whenever the phone is "on hook" (i.e. the switch (A4) is open), and other components which are connected when the phone is "off hook". The off-hook components include a transmitter (microphone, A2), a receiver (speaker, A1), and other circuits for dialing, filtering (A3), and amplification.
A calling party wishing to speak to another party will pick up the telephone's handset, thereby operating a lever which closes the switchhook (A4), which powers the telephone by connecting the transmitter (microphone), receiver (speaker), and related audio components to the line. The off-hook circuitry has a low resistance (less than 300 ohms) which causes a direct current (DC), which comes down the line (C) from the telephone exchange. The exchange detects this current, attaches a digit receiver circuit to the line, and sends a dial tone to indicate readiness. On a modern push-button telephone, the caller then presses the number keys to send the telephone number of the called party. The keys control a tone generator circuit (not shown) that makes DTMF tones that the exchange receives. A rotary-dial telephone uses pulse dialing, sending electrical pulses, that the exchange can count to get the telephone number (as of 2010 many exchanges were still equipped to handle pulse dialing). If the called party's line is available, the exchange sends an intermittent ringing signal (about 75 volts alternating current (AC) in North America and UK and 60 volts in Germany) to alert the called party to an incoming call. If the called party's line is in use, the exchange returns a busy signal to the calling party. However, if the called party's line is in use but has call waiting installed, the exchange sends an intermittent audible tone to the called party to indicate an incoming call.
The ringer of a telephone (A7) is connected to the line through a capacitor (A6), which blocks direct current but passes the alternating current of the ringing signal. The telephone draws no current when it is on hook, while a DC voltage is continually applied to the line. Exchange circuitry (D2) can send an AC current down the line to activate the ringer and announce an incoming call. When there is no automatic exchange, telephones have hand-cranked magnetos to generate a ringing voltage back to the exchange or any other telephone on the same line. When a landline telephone is inactive (on hook), the circuitry at the telephone exchange detects the absence of direct current to indicate that the line is not in use. When a party initiates a call to this line, the exchange sends the ringing signal. When the called party picks up the handset, they actuate a double-circuit switchhook (not shown) which may simultaneously disconnects the alerting device and connects the audio circuitry to the line. This, in turn, draws direct current through the line, confirming that the called phone is now active. The exchange circuitry turns off the ring signal, and both telephones are now active and connected through the exchange. The parties may now converse as long as both phones remain off hook. When a party hangs up, placing the handset back on the cradle or hook, direct current ceases in that line, signaling the exchange to disconnect the call.
Calls to parties beyond the local exchange are carried over trunk lines which establish connections between exchanges. In modern telephone networks, fiber-optic cable and digital technology are often employed in such connections. Satellite technology may be used for communication over very long distances.
In most landline telephones, the transmitter and receiver (microphone and speaker) are located in the handset, although in a speakerphone these components may be located in the base or in a separate enclosure. Powered by the line, the microphone (A2) produces a modulated electric current which varies its frequency and amplitude in response to the sound waves arriving at its diaphragm. The resulting current is transmitted along the telephone line to the local exchange then on to the other phone (via the local exchange or via a larger network), where it passes through the coil of the receiver (A3). The varying current in the coil produces a corresponding movement of the receiver's diaphragm, reproducing the original sound waves present at the transmitter.
Along with the microphone and speaker, additional circuitry is incorporated to prevent the incoming speaker signal and the outgoing microphone signal from interfering with each other. This is accomplished through a hybrid coil (A3). The incoming audio signal passes through a resistor (A8) and the primary winding of the coil (A3) which passes it to the speaker (A1). Since the current path A8 – A3 has a far lower impedance than the microphone (A2), virtually all of the incoming signal passes through it and bypasses the microphone.
At the same time the DC voltage across the line causes a DC current which is split between the resistor-coil (A8-A3) branch and the microphone-coil (A2-A3) branch. The DC current through the resistor-coil branch has no effect on the incoming audio signal. But the DC current passing through the microphone is turned into AC current (in response to voice sounds) which then passes through only the upper branch of the coil's (A3) primary winding, which has far fewer turns than the lower primary winding. This causes a small portion of the microphone output to be fed back to the speaker, while the rest of the AC current goes out through the phone line.
A lineman's handset is a telephone designed for testing the telephone network, and may be attached directly to aerial lines and other infrastructure components.
HISTORY
Before the development of the electric telephone, the term "telephone" was applied to other inventions, and not all early researchers of the electrical device called it "telephone". A communication device for sailing vessels The Telephone was the invention of a captain John Taylor in 1844. This instrument used four air horns to communicate with vessels in foggy weather. Later, c. 1860, Johann Philipp Reis used the term in reference to his Reis telephone, his device appears to be the first such device based on conversion of sound into electrical impulses, the term telephone was adopted into the vocabulary of many languages. It is derived from the Greek: τῆλε, tēle, "far" and φωνή, phōnē, "voice", together meaning "distant voice".
Credit for the invention of the electric telephone is frequently disputed. As with other influential inventions such as radio, television, the light bulb, and the computer, several inventors pioneered experimental work on voice transmission over a wire and improved on each other's ideas. New controversies over the issue still arise from time to time. Charles Bourseul, Antonio Meucci, Johann Philipp Reis, Alexander Graham Bell, and Elisha Gray, amongst others, have all been credited with the invention of the telephone.
Alexander Graham Bell was the first to be awarded a patent for the electric telephone by the United States Patent and Trademark Office (USPTO) in March 1876. The Bell patents were forensically victorious and commercially decisive. That first patent by Bell was the master patent of the telephone, from which other patents for electric telephone devices and features flowed.
In 1876, shortly after the telephone was invented, Hungarian engineer Tivadar Puskás invented the telephone switch, which allowed for the formation of telephone exchanges, and eventually networks.
WIKIPEDIA
Electronic keypad locks, no smart card (such as BikeLink) needed. You stash your bike, close the door, enter a code to secure the door. To retrieve the bike later, you enter the same code so the door pops open. I really like this system.
This ATM keypad overlay allows the underlying keypad to function properly while it stores all keystrokes put into an ATM (i.e., your PIN).
Note this back side view shows the devices electronics.
The small black skimmer fits over the card slot on an ATM machine and records all the data on the cards magnetic strip for later download onto a computer.
Visit www.insideIDtheft.info for a video demonstration of a credit card skimmer.
We do NOT sell any equipment.
Life is a form of Ctrl,it is us who Ctrl our life or fate shall determined everything?
P.s: It is of my interest to be involved in conceptual macro. I ain't using any macro lens,but i am just using reverse ring/adapter from USA to plug my lens backwardly. I ordered it through my friend who went to United States recently. Above is the keypad of my Nokia E63,kinda outdated phone. xD
3125 W Silver Lake Rd, Fenton, MI
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Here's a shot of the upper portion of the telephone's keypad.
All photos protected by copyright, you do not have permission to use or remove.
Press L on your keypad.
7-17-11
Well, I guess my cousin Robin was serious when he got "SIK OF U" on his plates for his chopper. It all started Sunday when had planned a bike ride over to Oakford. I made my way to Virden and after a few last minute preparations we were on our way. I suited up, started my bike (which never has any problems mind you, it's a Honda) and pulled around front where his chopper was parked. Zzzzziiiing. Zzzzziiiiiiiiiiiiinnngggg. That's all we heard as Robin hit the starter button and instantly we knew, the starter had gone bad. Well shit, that totally sucks! After kicking rocks for a few minutes we decided to make our way over to Oakford anyway, by vehicle which wasn't quite as scenic by bike of course. I think Rob got a little sick of hearing me ask if he was finally going to list his chopper on Craigslist and get himself a dependable Honda. By the time we arrived back to Rob's place he had sunken further into this catatonic stupor like state. He was clearly bummed out. We made our way to the back yard to have a seat and talk a bit about the day. We conversed about the fact that it was a good thing the starter decided to go out BEFORE making our hour and a half trip to Oakford, and not having it happen there. That would have really sucked! At one point, Rob got up and went into the lawnmower shed. I watched as he crossed the lawn, gas can in hand, still in this odd incoherent state. I thought nothing of it, I figured he was just prepping to mow the yard for the next day. Then there was a loud WOOMPF! that came from the driveway. You know, the sound that lots of gasoline makes when you throw a match into it? I sprang to my feet and dashed to the driveway to see Robin angrily screaming at the top of his lungs, "We don't need no water, let the motherfucker burn!!!" It was almost as if all his tension was being released at once. The stupor had clearly vanished, an eerie teeth grinding grin resting on his face. But was he in his right mind... ?
14-24mm
sb900/diffused @ 1
ttl cord
Want to be a part of my 365 Project and get your photo taken? Got an idea/concept? Contact me, Don't be shy! Let's create art!
This is Birmingham New Street Station as seen from Navigation Street.
This is the entrance to the Construction Site / demolition site of the former lower car park. The first stage to redevelop New Street Station.
The signs advices drivers to use the upper car park around the corner off Hill Street and up the ramp.
A turnstile gate to the site. With keypad.
Alarm systems include: Texecom Premier Elite 64W, Texecom Capture Latest Motion Sensors, Texecom Micro Door Contact, Texecom Wireless Sounder, Texecom Wired Keypad, Smartcom.
Electospace Autovon phone keypad closeup. Another version was manufactured with a membrane keypad (entire face was flush - same as black buttons above keypad).
Red buttons on dial pad bump routine voice telephone traffic based on call urgency -- if another circuit to the destination is unavailable.
FO = Flash Override
F = Flash
I = Immediate
P = Priority
System is no longer in service, and sets have been showing up on the surplus market for many years.
Electrospace sets are digital, and can't be plugged into a analog home line (they require their own proprietary digital switch). Most older first generation Western Electric Autovon sets are analog, and can be used as "home" phones without modification.
LCD status screen at top.
A detailed technical overview of the AUTOVON system may be found in "Bell Laboratories Record," April 1968.
Go to "Original Size" of 3072 x 2304 for more detail.
In today's world of cell phones and cordless phones and Bluetooth and all manner of computer based video calling, a phone with a cord is an oddity. A rarity. It's like seeing a Jackalope...At least around here.
But I can remember spending oh-so many late nights as a teenager whispering into the kitchen telephone while lying on the floor, wrapping the twisted cord around my finger. The trick was to tiptoe from my room to the phone without getting caught because it was way past my parents' bedtime. Then, I could spend blissful, hushed, hours talking to my boyfriend about matters that seemed to get vastly more important as the night raced by in the dark of the kitchen.
Maybe that's why I smile every time we have to take this phone out and put it to use after a big storm kills the power and, therefore, our cordless phones. My kids giggle and the absurdity of being tethered on one location. I, on the other hand, twist the cord around my finger and remember...
115 Pictures in 2015 #82: Nostalgia
Twitter Tuesday: #Phone
Compstyle font on an old electronic door lock interface.
Makes me think of Space 1999 when I see this.
We A-Teamers hacked a knitting machine's keypad so that an Arduino could type on it. This portion of the project took a single day.
This is the logic probe that I built in about 1980, cased in an aluminium cigar tube. The metal is only slightly thicker than tinfoil, hence the various "dings" that are visible! The chip is a CMOS CD4049, and the circuit came from an article in ETI (Electronics Today International), December 1979, page 101.
The USB keyboard controller is mounted to the back of the LCD.
I would perfer it to be internal, but there isn't enough room.
Work in progress on the HEX keypad. The generic 6425 push buttons & keytops get BECC self-adhesive vinyl lettering used by modellers. The key switches are mounted on conventional copper strip veroboard, with the IC sockets installed on Protoboard-3U.
False keypad and credit card ATM
As I left work in the ITN News studio one evening in 2007, I glanced across Grays Inn Road to the NatWest ATM which had a fair crowd around it...I saw what looked like a skimming crew who after checking both ways up the street (but not over to me) ripped this facia off the ATM and handed it to an accomplice who hotfooted it down the road and into the Bourne Estate.
Wired keypad that needs 24V input from the door drive. Integrated card reader, 1 card supplied in the package.Including red/green LED indicators and blue backlight keys. Optional extra cards available. Entrance security!
See our online catalogue for more information!
When you play a first-person-shooter, it sometimes takes you a while to get into what I'm rather pompously going to refer to as the umwelt of the game. The world doesn't quite fit, somehow. It's nothing to do with the configuration of the keyboard and mouse, it's getting used to how your character moves around in game-space.
In Deus Ex, you're some sort of cyborg guy. This means that whenever you approach an object or person, little bouncing corners appear around it, and a description appears at the top. A handy bit of augmented reality for those with poor memory.
Each time I got back into the umwelt of the game, I had the same experience, as I reached the keypad outside my work. I leant in, to type in the code, and was shocked when those comforting bouncing corners failed to appear.
On the right hand side of my computer keypad I keep a pad of paper for rough notes. As you see this is made from scrap sheets of A4 paper cut in half lengthways. I punch a hole in them and keep them in place with this rather nice screw stud which my wife gave to me about twenty years ago. When the sheet is finished I tear it off the stud and clip the sheets together. Here you see old sheets held with a small Bulldog* clip.
*"BULLDOG" is a registered trademark of Brandsley Limited which is licensed to Faire Bros & Co Limited. Its registration as a trademark in the United Kingdom dates back to 1944.