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Handset
Handset
Handset
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Classic handset
Woman using a telephone handset (West Germany, 1988)
Early 20th century candlestick telephone which required only the receiver to be held to the ear (United States, 1920s–30s)

A handset is a component of a telephone that a user holds to the ear and mouth to receive audio through the receiver and speak to the remote party using the built-in transmitter. In earlier telephones, the transmitter was mounted directly on the telephone itself, which was attached to a wall at a convenient height or placed on a desk or table. Until the advent of the cordless telephone, the handset was usually wired to the base unit, typically by a flexible tinsel wire cord.

The handset of a cordless telephone contains a radio transceiver which relays communication via a base station that is wired to the telephone line. A mobile phone does not require a base station and communicates directly with a cell site in designated frequency bands.

Handset symbol

[edit]
Wikimedia Commons has media related to Handsets.

A graphic symbol that designates a handset is used on cordless and mobile phones to specify placing or ending a telephone call. Usually a button with green upright (off-hook) handset icon is used for starting a call, and a red lying-down (on-hook) handset is used for ending a call.[1] Unicode has the handset symbol U+1F4DE 📞 TELEPHONE RECEIVER commonly faced rightwards to use with face emojis, and also symbols with specified direction: U+1F57B 🕻 LEFT HAND TELEPHONE RECEIVER, and U+1F57D 🕽 RIGHT HAND TELEPHONE RECEIVER.[2]

See also

[edit]

References

[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Handset

View on Grokipedia
from Grokipedia
A handset is a combined telephone transmitter and receiver mounted on a handheld device, allowing users to speak into the microphone at one end while listening through the speaker at the other during calls. This ergonomic design, which separates the mouthpiece and earpiece on a single handle, distinguishes it from earlier separate components in telephones. The concept of the handset emerged in the late as evolved from Alexander Graham Bell's 1876 of the basic . Early prototypes appeared in the United States in 1878 and in 1879, but widespread adoption began in the mid-1880s through innovations by Swedish firm . engineers Anton Avén and Leonard Lundqvist, in collaboration with Stockholms Allmänna Telefonaktiebolag (SAT), developed the first practical handset model in 1884, with manufacturing starting in 1885 initially for telephone operators at a cost of 55 kronor. By 1892, compact versions were integrated into consumer models like the "Dachshund" and "Coffee-grinder" telephones, enabling single-handed operation relative to prior box-style designs and facilitating Europe's first multiple-line switchboards. Over the , handsets became standard in desk telephones, evolving with materials like in the 1940s and electronic components for improved audio quality. In and mobile contexts, the term extends to portable devices, though traditionally it refers to the fixed telephone's handheld unit containing a and dynamic speaker. Today, while digital VoIP systems and smartphones have reduced reliance on physical handsets, they remain integral to business phones, headsets, and legacy setups for clear voice transmission.

Definition and Types

Definition

A handset is the portable component of a designed to be held to the user's for receiving audio through the receiver and to the mouth for transmitting speech via the , typically integrated into a single ergonomic unit connected by a . This design allows for convenient one-handed operation during voice communication in systems. In terms of basic functionality, the receiver within the handset converts incoming electrical signals into audible waves, often employing electromagnetic principles where an varies the movement of a diaphragm to reproduce the original audio. Conversely, the transmitter captures waves from the user's voice, transforming them into electrical signals through mechanisms such as a vibrating diaphragm modulating current flow in carbon granules in older models, or electret condenser microphones in modern variants, where a permanently charged diaphragm generates voltage variations in response to . The scope of handsets in telephony includes both wired variants, connected via cords to a base unit, and wireless (cordless) variants that operate through radio frequency links to a charging base, but excludes complete standalone communication devices such as portable radios that lack integration with telephone networks.

Classification of Handsets

Handsets are primarily classified by their connectivity method, which determines how they interface with communication networks, as well as by form factor and underlying technology that influence portability, durability, and functionality. This taxonomy helps distinguish between traditional fixed-line devices and more advanced variants, reflecting advancements in from physical cabling to cellular and internet-based systems. Wired handsets, also known as corded handsets, connect directly to a base unit or via physical cables, typically twisted-pair wiring, and were the dominant form in from the early through the . These devices offer reliable, interference-free transmission but limit user mobility to the cord length, often around 1-3 meters, making them suitable for stationary desk use in homes and offices. Cordless handsets operate on battery power and establish a short-range radio link to a fixed base station connected to the public switched telephone network (PSTN), providing greater freedom of movement within a home or small office, typically up to 50-300 meters outdoors. Introduced in the 1970s with early analog models, they gained widespread adoption in the 1990s through standards like Digital Enhanced Cordless Telecommunications (DECT), formalized by the European Telecommunications Standards Institute (ETSI) in 1992 and commercially launched in 1993. DECT handsets use digital signals in the 1.9 GHz band for improved security and audio quality over analog predecessors. Mobile handsets, or cellular phones, are self-contained devices that communicate wirelessly via radio frequencies with cell towers, enabling global mobility without a fixed base. Their evolution spans generations: first-generation () analog systems emerged in the 1980s, supporting voice calls at speeds up to 2.4 kbps; second-generation () introduced digital /CDMA in the 1990s for basic data; third () in the 2000s added mobile internet; fourth (4G LTE) in the 2010s enabled high-speed streaming; and fifth-generation () networks, deployed from the late 2010s onward, support ultra-low latency and speeds exceeding 1 Gbps for applications like . Specialized handsets adapt standard designs for demanding environments or operational needs, such as rugged variants built to IP67 standards for dust and water resistance in industrial settings like or sites. These often incorporate reinforced casings and shock-absorbing materials to withstand drops and vibrations. Headsets, which combine earpieces and microphones in over-ear or in-ear forms, provide an alternative to handsets for hands-free operation in professional settings like , healthcare, or field services, often featuring noise-canceling for high-decibel environments. Emerging classifications include Voice over Internet Protocol (VoIP) handsets, which leverage (SIP) for internet-based calling, compatible with softphones and systems for seamless integration with cloud PBX. Post-2020 developments in VoIP systems have incorporated AI features such as intelligent call routing and virtual assistants to enhance productivity in hybrid work setups.

Historical Development

Early Inventions

The handset emerged as a key component of following Alexander Graham Bell's foundational US Patent 174,465, granted on March 7, 1876, for "Improvement in ," which described a system for transmitting vocal sounds electrically but featured designs with separate mouthpiece (transmitter) and earpiece (receiver) components housed in a wooden box. While early telephones based on this patent required users to hold the transmitter to the mouth and the receiver to the ear independently, limiting convenience and contributing to the evolution toward integrated devices, prototypes of combined handsets appeared in the United States in 1878 and in 1879. Widespread adoption began in the mid-1880s through innovations by Swedish firm , whose engineers developed the first practical handset model in 1884. In the United States, a significant advancement occurred with the development of the first combined handset by around 1927, which integrated the transmitter and receiver into a single unit connected by a flexible cord, replacing the cumbersome designs that had dominated since the late . This innovation allowed for more practical one-handed operation and marked a shift from desk-mounted separate elements to portable, user-friendly receivers. Key early models, such as Western Electric's 102 set introduced in 1927 and the 202 set in 1930, further refined this concept with an ergonomic curved shape that facilitated comfortable holding during conversations, becoming a standard for residential and office use. Early handsets incorporated durable materials like , a molded phenolic resin, for casings starting in the 1920s, providing electrical insulation, heat resistance, and aesthetic appeal while enabling of lightweight yet robust components. Transmission relied on carbon microphones, whose practicality was enhanced by Thomas Edison's US Patent 378,044, granted on February 14, 1888, for an improved telephone transmitter that utilized a carbon granule design to amplify voice signals more reliably, paving the way for effective integration in combined handsets. These developments laid the groundwork for corded systems.

20th Century Advancements

Following World War II, the mass production of telephone handsets entered a new era with the widespread integration of rotary dials into standardized designs, facilitating easier direct dialing and reducing reliance on operator assistance. In the United States, the Western Electric Model 500, introduced in 1949, became the iconic standard for the Bell System, featuring a rotary dial, improved anti-sidetone circuitry, and modular components that enabled efficient manufacturing on a massive scale, with millions produced over the subsequent decades. This model exemplified post-war advancements in assembly line techniques, drawing from wartime industrial efficiencies to produce durable, bakelite-bodied handsets that were distributed globally through national telephone networks. In the United Kingdom, similar progress occurred during the 1940s and 1950s, as the General Post Office (GPO) refined handset designs for rotary operation, culminating in the 1960s with the GPO 746 model, introduced in 1967 and standardized by 1970 as the primary residential telephone, incorporating a lightweight plastic casing and balanced ringer for enhanced usability. Material innovations in the marked a significant shift from , the dominant thermosetting plastic since the 1930s, to materials like (ABS), which offered superior moldability, impact resistance, and reduced weight without compromising structural integrity. handsets, while revolutionary for their time due to their heat resistance and electrical insulation, were heavy and prone to brittleness; ABS allowed for sleeker, more ergonomic designs that weighed up to 30% less, improving user comfort during prolonged calls and enabling colorful finishes beyond traditional black. This transition, adopted by manufacturers such as and the GPO, aligned with broader trends toward lighter, more aesthetic products, contributing to higher adoption rates in homes and offices. A key technological refinement in handset audio components came with the introduction of in the , which replaced earlier carbon granule transmitters for superior performance. Invented by James West and Gerhard Sessler at Bell Laboratories, the —patented in 1962—utilized a permanently charged material to achieve higher sensitivity, lower levels, and more consistent , making voice transmission clearer over long distances. By the mid-, these microphones were integrated into production handsets, reducing and hiss common in carbon types, and they became standard in models like the GPO 746, enhancing overall call quality without requiring external power sources for the . The late 1970s saw the advent of cordless handsets, freeing users from wired constraints within home or office environments through low-power radio transmission to a . The first commercial cordless telephones emerged in in 1977, developed by companies like under NTT oversight, using analog frequencies for short-range operation and marking an early step toward wireless telephony. , regulatory hurdles delayed widespread adoption until the 1980s, when the (FCC) approved expanded spectrum allocations, including 10 additional channels in the 46/49 MHz band in December 1983, allowing manufacturers to produce interference-resistant models with ranges up to several hundred feet. These approvals spurred market growth, with cordless phone sales surging from 50,000 units in 1980 to over 1 million by 1982, driven by demand for mobility. By the early 1990s, global standardization efforts culminated in the European Telecommunications Standards Institute (ETSI) releasing the Digital Enhanced Cordless Telecommunications (DECT) specification in 1991, establishing a unified framework for digital cordless operation across . DECT utilized (TDMA) in the 1880–1900 MHz band to provide secure, interference-free communication with typical indoor ranges of up to 50 meters and outdoor ranges extending to 100 meters, supporting multiple handsets per base and handover capabilities. This standard, formalized through Council Directive 91/287/EEC, facilitated cross-border compatibility and paved the way for scalable cordless systems, influencing designs worldwide while maintaining with analog predecessors.

Technical Components

Acoustic Elements

The receiver, or earpiece, in a telephone handset functions as a speaker that converts electrical signals into sound waves for the listener. Traditional designs predominantly employ dynamic speakers, which use a moving coil mechanism to drive a diaphragm, ensuring efficient reproduction of voice frequencies. These dynamic receivers typically operate within a frequency range of 300–3400 Hz, optimized to capture the fundamental harmonics of human speech for clear intelligibility. Piezoelectric speakers, utilizing ceramic materials that deform under electrical voltage to produce sound, are also incorporated in some modern or specialized handsets, offering compact size and durability, though they are less common in standard telephony due to narrower frequency response compared to dynamic types. The transmitter, or microphone, captures the user's voice by converting acoustic pressure into an electrical signal for transmission. Early handsets relied on carbon microphones, which modulated current through varying carbon granule resistance under sound pressure, but these suffered from high noise and limited fidelity. Condenser microphones, including electret variants, became prevalent; electret microphones, featuring a permanently charged dielectric material to maintain the capacitor charge without external bias voltage, emerged in the 1960s and dominated handset applications by the 1970s due to their improved sensitivity and high-fidelity response. Today, electret types remain the standard in most handsets for their reliability and cost-effectiveness in voice capture. Acoustic design principles in handsets enhance amplification and clarity. The earpiece often incorporates a Helmholtz resonator configuration, where an enclosed cavity and neck-like path resonate at specific frequencies to amplify output without additional power, improving efficiency in the voice band. In modern variants, noise-canceling ports on the —typically front and rear openings—enable differential sensing to subtract ambient , providing at least 6 dB of cancellation by focusing on the user's voice. Standard sound pressure levels from the earpiece range from 70–90 dB SPL at the reference point, calibrated for comfortable listening during typical calls, with measurements often targeting around 80–94 dB at 1 kHz in standardized artificial setups. is maintained below 5% across the voice frequency band to preserve audio fidelity, ensuring minimal coloration of the signal. For the , the basic transmission relationship is given by the sensitivity : Vout=S×PV_\text{out} = S \times P where VoutV_\text{out} is the output signal voltage in volts, SS is the microphone sensitivity in V/Pa, and PP is the input in pascals (Pa). This linear model quantifies how acoustic input translates to electrical output, with typical sensitivities around -40 to -30 dBV/Pa for handset use.

Electrical and Structural Features

Wired handsets typically employ RJ11 modular plugs, specifically the 6P4C configuration with four contacts, to connect the handset cord to the base, ensuring reliable transmission of analog signals over twisted-pair wiring. In contrast, handsets integrate RF modules and antennas operating in the 2.4 GHz ISM band for wireless communication with the base station, enabling mobility while adhering to unlicensed spectrum regulations for low-power devices. Power systems in cordless handsets evolved from nickel-cadmium (NiCd) batteries predominant in the and early , which provided robust performance but suffered from , to nickel-metal hydride (NiMH) cells widely adopted through the and for improved and reduced environmental impact. Modern cordless models post-2000 predominantly use lithium-ion (Li-ion) batteries, offering higher capacity and lighter weight, with typical talk times reaching up to 10 hours on a single charge under standard usage conditions. Structural materials for handset housings commonly include plastic, valued for its high impact resistance and ability to withstand drops and mechanical stress without cracking, making it suitable for everyday handling. Ergonomic design incorporates curves derived from anthropometric data on hand dimensions and grip preferences, with optimal handset weights ranging from 150 to 200 grams to minimize during prolonged use while maintaining balance for natural holding positions. Early handset circuitry relied on analog amplifiers to boost weak signals from the before transmission, using simple transistor-based designs integrated into the rather than the handset itself for power efficiency. In digital handsets introduced in the 1990s, (DSP) chips became standard, enabling advanced functions such as echo cancellation through adaptive filtering algorithms that model and subtract acoustic reflections in real-time. Rugged variants of handsets, designed for industrial or harsh environments, achieve IP54 ratings for protection against dust ingress and water splashes, combined with MIL-STD-810 compliance for resistance to shocks, vibrations, and extreme temperatures.

Modern Applications

In Fixed Telephony

In fixed telephony, handsets play a central role in Plain Old Telephone Service (POTS), which provides voice-grade analog telephone service over copper twisted-pair wiring using analog signal transmission. These handsets are fully compatible with two-wire analog interfaces, enabling basic voice communication while supporting Dual-Tone Multi-Frequency (DTMF) signaling for touch-tone dialing and interactive services like menu navigation. This compatibility ensures seamless integration with traditional central office switches, maintaining reliability in environments where digital alternatives may not yet be feasible. As fixed telephony evolves toward internet-based systems, handsets have adapted for Voice over (VoIP) through USB or Ethernet connections, as seen in devices like Cisco IP phones that leverage the Session Initiation Protocol (SIP) for establishing and managing calls over IP networks. SIP, defined in IETF RFC 3261, standardizes signaling for multimedia sessions, allowing these handsets to handle high-fidelity audio while supporting features like encryption and prioritization. In desk phone setups, multi-line handsets integrate LCD displays for , a feature that became standard in the 1990s following FCC rules mandating caller identification transmission in analog systems. These displays show incoming numbers and names, enhancing call management in business environments with multiple extensions. Accessibility enhancements in fixed handsets address needs for hearing-impaired users, including amplified receivers offering up to 40 dB gain to boost incoming audio volume and adjustable tone controls for clarity. Many models also feature T-coil (telecoil) compatibility, enabling with hearing aids to minimize feedback and improve sound induction without additional accessories. By 2025, new installations of traditional fixed handsets have declined sharply due to the widespread adoption of fiber-to-the-home (FTTH) networks, which prioritize all-digital services over legacy infrastructure. However, ongoing support for existing POTS handsets persists through Analog Telephone Adapter (ATA) devices, such as Cisco's ATA 180 series, which convert analog signals to VoIP for integration with fiber-based systems. This transitional approach ensures continued functionality amid telecom shifts, particularly in regions phasing out lines.

In Mobile and Wireless Systems

In mobile and wireless systems, handsets have evolved into portable devices central to cellular communication, beginning with the second-generation () Global System for Mobile Communications () standard introduced in the early . This shift from analog to digital networks enabled reliable voice calls and short messaging on compact, battery-powered handsets, with early models like the Motorola StarTAC exemplifying the transition to pocket-sized portability. By the late , GSM's global adoption supported over 1 billion subscribers, laying the foundation for subsequent generations that integrated data services. The progression continued with third-generation () Universal Mobile Telecommunications System () in the early 2000s, adding mobile , followed by fourth-generation () Long-Term Evolution (LTE) around 2009 for high-speed . The fifth-generation () New Radio (NR) standard, commercially rolled out in 2019, revolutionized handset capabilities by supporting enhanced mobile with peak speeds exceeding 10 Gbps, ultra-reliable low-latency communication for real-time applications, and massive connectivity for IoT devices. Contemporary 5G handsets incorporate millimeter-wave (mmWave) bands, typically in the 24-40 GHz range, to achieve high-speed voice transmission with sub-10 ms latencies, particularly in urban dense deployments where efficiency is critical. Beyond cellular networks, handsets using the Digital Enhanced Cordless Telecommunications (DECT) standard serve as wireless extensions in home and office settings, operating on unlicensed 1.9 GHz bands for interference-free voice. A single DECT base station can support up to 10 handsets simultaneously, with typical ranges of 50 meters indoors and 300 meters outdoors under ideal conditions, enabling multi-user systems for small businesses or residences without relying on cellular infrastructure. Bluetooth and Wi-Fi handsets facilitate standalone Voice over Wi-Fi (VoWiFi) calling, leveraging internet protocols for cost-effective communication independent of cellular coverage. These devices support seamless between Wi-Fi and cellular networks and integrate with smart home platforms, such as Amazon Echo ecosystems, where handsets can initiate or receive calls via Alexa-enabled voice commands for hands-free operation. As of 2025, emerging advancements include prototypes exploring terahertz frequencies (0.1-3 THz) to enable terabit-per-second data rates and integrated sensing-communications, with early demonstrations focusing on short-range, high-capacity links for next-generation handsets. Foldable handsets enhance in satellite-linked systems, such as Starlink's direct-to-cell architecture, which supports voice services on compatible devices for global connectivity in underserved areas, reducing reliance on traditional towers. Security features in these wireless handsets emphasize , as seen in applications like Signal, where mobile devices act as secure endpoints to protect voice calls and messages from interception, ensuring only intended recipients can access content using open-source protocols like the .

Symbolism and Representation

Iconographic Symbols

The traditional iconographic symbol for a telephone handset is an upright black outline depicting the receiver and , commonly used in signage to denote telephone services. This symbol was standardized by the (ITU-T) in Recommendation E.121, which specifies a telephone handset in an upper left-lower right orientation with the directed upwards. First published in 1988 by the CCITT (predecessor to ITU-T), the recommendation aimed to provide universally recognizable pictograms for international telecommunication services. Variants of the handset symbol incorporate colors and orientations to indicate status in user interfaces and telephony equipment. For instance, a green handset icon often signifies an off-hook or active call state, while red denotes a muted call, as seen in LED indicators on IP phones from manufacturers like Cisco. These color conventions align with broader human interface guidelines for intuitive status feedback in communication devices. In digital standards, the classic handset is represented by Unicode character U+1F4DE (📞), known as "Telephone Receiver," introduced in in 2010. This depicts a traditional receiver at a 45-degree angle and is used for content related to calls and communication. Variants include combinations such as 📞 with an arrow to indicate incoming calls, though no standalone Unicode exists for this specific form; instead, it relies on emoji sequencing. The evolution of handset iconography traces from rudimentary representations in teletype systems, where simple character-based drawings approximated phone shapes using available glyphs, to modern vector-based emojis in the . Graphically, the standard handset icon features a 45-degree angled receiver for optimal visibility and balance in both horizontal and vertical layouts, typically rendered in scalable vector format () to ensure clarity across sizes from signage to mobile screens. This orientation, as defined in E.121, facilitates intuitive recognition by aligning with natural hand-holding postures.

Digital and Cultural Usage

In user interfaces, the serves as a universal symbol for functions, prominently featured in mobile operating systems to initiate or manage calls. For instance, in iOS dialer apps, the icon represents the phone interface, adhering to Apple's which specify black and clear color schemes for scalable symbols to ensure clarity across devices. Similarly, Android's incorporates handset variants within its symbol library, such as the outlined phone icon for call buttons in dialer applications, promoting consistency in app navigation. These icons emerged as standard post-2007 with the advent of smartphones like the , replacing physical buttons with intuitive visual cues for voice communication. Animations of the handset enhance user feedback, particularly for incoming calls, where vibrating or pulsing effects simulate ringing to alert users without auditory cues. Such dynamic representations, common in both and Android apps since the late 2000s, improve by providing visual alternatives to sound notifications, as seen in libraries of animated icons designed for mobile UI integration. Culturally, the handset has symbolized connectivity and status in media, notably in 1980s films where bulky devices like the Motorola DynaTAC in (1987) represented corporate power and excess among elites. This portrayal reinforced the handset as an emblem of professional ambition and instant communication in an era of economic deregulation. In contemporary digital culture, the persists as a nostalgic trope in and memes, often evoking humor around outdated communication rituals, such as the "pick up the phone" scenario where characters dramatically answer calls amid comedic delays—a motif echoed in viral content and trope analyses of media narratives. Accessibility considerations for handset icons emphasize high-contrast adaptations to support users with visual impairments, aligning with WCAG 2.1 Success Criterion 1.4.11, which mandates a minimum 3:1 between the icon and adjacent colors for essential graphical elements like phone symbols. Examples include white icons on orange backgrounds achieving this threshold, ensuring without relying on color alone.

References

  1. https://www.merriam-webster.com/dictionary/handset
  2. https://www.dictionary.com/browse/handset
  3. https://www.loc.gov/everyday-mysteries/technology/item/who-is-credited-with-inventing-the-telephone/
  4. https://www.ericsson.com/en/about-us/history/products/the-telephones/the-telephone-handset--a-successful-introduction
  5. https://www.pcmag.com/encyclopedia/term/handset
  6. https://www.collinsdictionary.com/us/dictionary/english/handset
  7. https://personal.utdallas.edu/~torlak/courses/ee4367/lectures/lecture1.pdf
  8. https://www.thoughtco.com/how-a-telephone-works-1992551
  9. https://www.energystar.gov/sites/default/files/specs//ENERGY_STAR_Telephony_Draft_Test_Method_RevSept2011_0.pdf
  10. https://www.sciencedirect.com/topics/computer-science/wireless-system
  11. https://www.wifihire.co.uk/what-are-landline-phones/18076/
  12. https://www.howstuffworks.com/telephone.htm
  13. https://www.abt.com/learn/telephone-buying-guide
  14. https://www.sciencedirect.com/topics/computer-science/cordless-phone
  15. https://www.gigaset.com/hq_en/cms/dect.html
  16. https://www.geeksforgeeks.org/computer-networks/what-is-digital-enhanced-cordless-telecommunications-dect/
  17. https://www.cengn.ca/information-centre/innovation/timeline-from-1g-to-5g-a-brief-history-on-cell-phones/
  18. https://techbuzz.att.com/explainers/history-of-the-mobile-phone-from-1g-to-5g/
  19. https://www.yealink.com/en/product-detail/zoom-phone-w59r
  20. https://www.zebra.com/us/en/products/mobile-computers/wearable-computers/hs3100.html
  21. https://www.sip.us/blog/latest-news/sip-vs-voip-whats-difference/
  22. https://www.wildix.com/
  23. https://americanhistory.si.edu/collections/object/nmah_704159
  24. https://ethw.org/Telephones
  25. http://www.arctos.com/dial/
  26. https://www.plasticstoday.com/materials/the-unbreakable-black-beauty-that-changed-communication-forever
  27. https://www.thomasedison.org/edison-patents
  28. https://telephonesuk.org.uk/phones-1960-80/
  29. https://www.aps.org/apsnews/2023/04/electret-microphone
  30. https://clickamericana.com/topics/science-technology/the-latest-and-greatest-telephones-1987
  31. https://www.nytimes.com/1983/02/12/style/cordless-phones-ring-up-sales-and-riddles.html
  32. https://www.etsi.org/technologies/dect
  33. https://www.legislation.gov.uk/eudr/1991/287/introduction
  34. https://patents.google.com/patent/CN203181025U/en
  35. https://microphone238.weebly.com/carbon--electret-microphones.html
  36. https://hackaday.com/2021/02/17/james-west-began-40-years-at-bell-labs-with-world-changing-microphone-tech/
  37. https://www.armoredphones.com/Noise-Canceling-Handset.html
  38. https://www.ioa.org.uk/system/files/proceedings/r_cross_telephone_handset_design.pdf
  39. https://www.analog.com/en/resources/analog-dialogue/articles/understanding-microphone-sensitivity.html
  40. https://www.kleintools.com/catalog/twisted-pair-connectors/modular-telephone-plugs-rj11-6p4c-25-pack
  41. https://telephones.att.com/buying-guide/cordless-phone-buying-guide
  42. https://shop.panasonic.com/products/cordless-phone-kx-tgd83x-series
  43. https://www.siniwo.com/news/what-are-the-advantages-of-abs-plastic-telephone-handset/
  44. https://www.etsi.org/deliver/etsi_etr/100_199/166/01_60/etr_166e01p.pdf
  45. https://www.eetimes.com/wireless-and-dsp-backgrounder/
  46. https://www.cisco.com/c/en/us/products/collateral/collaboration-endpoints/wireless-ip-phone-8821/datasheet-c78-737346.html
  47. https://www.spectralink.com/products/dect/s-series-handsets/
  48. https://bidcondocs.delaware.gov/DTI/DTI240046-TEL_SVC-rfp.pdf
  49. https://www.faa.gov/documentLibrary/media/Order/JO%25206000.200.pdf
  50. https://repository.upenn.edu/bitstreams/a93d83c0-d14f-43b5-86c9-baa19d318dfe/download
  51. https://wiki.voip.ms/article/IP_Phones
  52. https://docs.fcc.gov/public/attachments/FCC-11-100A1.pdf
  53. https://www.captel.com/2025/08/telephone-devices-for-hard-of-hearing/
  54. https://www.maxiaids.com/category/telephones2/a
  55. https://blog.telegeography.com/the-last-call-for-landline-telephony-not-yet
  56. https://www.cisco.com/c/en/us/products/unified-communications/ata-180-series-analog-telephone-adaptors/index.html
  57. https://www.ifaxapp.com/analog-to-digital-fax/are-landlines-being-discontinued/
  58. https://www.rfpage.com/evolution-of-wireless-technologies-1g-to-5g-in-mobile-communication/
  59. https://www.microwavejournal.com/articles/33936-the-evolution-of-cellular-technology-the-long-road-to-5g
  60. https://www.qualcomm.com/5g/what-is-5g
  61. https://support.yealink.com/en/portal/knowledge/show?id=6629cc31564d826f28104775
  62. https://www.grandstream.com/products/ip-voice-telephony/dect-cordless
  63. https://www.celona.io/5g-lan/5g-mmwave
  64. https://www.amazon.com/Echo-Hub/dp/B0BCR7M9KX
  65. https://www.idtechex.com/en/research-report/6g-market/1126
  66. https://ucpcba.com/6g-pcb-high-frequency/
  67. https://tech.yahoo.com/phones/articles/t-mobile-bringing-starlink-phone-221600498.html
  68. https://signal.org/legal/
  69. https://www.bbc.com/news/articles/c1kjd091019o
  70. https://www.itu.int/rec/T-REC-E.121/en
  71. https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-E.121-198811-S!!PDF-E&type=items
  72. https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cuipph/8831/10_3_1/english/UserGuide/CS38_BK_U841D454_00_userguide-8831/CS38_BK_U841D454_00_userguide-8831_chapter_01.pdf
  73. https://www.unicode.org/emoji/charts/full-emoji-list.html
  74. https://emojipedia.org/telephone-receiver
  75. https://www.asciiart.eu/electronics/phones
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