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worked by converting sound into an electrical signal via a 'liquid transmitter'. ... This created a varying strength electric signal that travelled down a wire to a receiver, where through a reversed process, the sounds were re-created -
allowed a single telephone to connect to multiple lines through a central switchboard -
were communicated orally to a switchboard operator when initiating a call. -
To dial a number the user would insert their finger into the number required. The deal would then be rotated around until they hit the finger stopper and would hear a soft clicking noise. After removing their finger, the dial would return to its starting position ready for the next number's input under spring action -
The Bell System introduced the first electronic push-button telephone system with touch-tone dialing to customers in Pennsylvania on November 18, 1963. Using dual-tone multi-frequency (DTMF) technology provided “touch-tone” service that would become the worldwide standard for telecommunication signaling. -
The handset receives the radio signal from the base, converts it to an electrical signal and sends that signal to the speaker, where it is converted into the sound you hear. ... The base receives your voice signal, converts it to an electrical signal and sends that signal through the phone line to the other party -
They were two-way radios that allowed people like taxi drivers and the emergency services to communicate. Instead of relying on base stations with separate cells (and the signal being passed from one cell to another), the first mobile phone networks involved one very powerful base station covering a much wider area -
AMPS allocates frequency ranges within the 800 and 900 Megahertz (MHz) spectrum to cellular telephone. ... The signals in the adjacent cell are sent and received on different channels than the previous cell's signals to so that the signals don't interfere with each other -
The StarTAC held 100 phone numbers and had several large buttons on the keypad and spines. The StarTAC was one of the first phones to use a vibration motor so you could silently accept calls. Pull-out antennas were common in the mid- to late 1990s, and even persisted into the early 2000s -
In its first appearance onscreen and in Jobs's hand, the phone looked like a sleek but inanimate black rectangle. Then, Jobs touched the screen. Suddenly, the featureless rectangle became an interactive surface. Jobs placed a fingertip on an on-screen arrow and slid it from left to right