SMDS(Switched Multi-megabit Data Services)
SMDS, which stands for Switched Multi-megabit Data Services, was a connectionless service used to connect LANs, MANs and WANs to exchange data. SMDS was based on the IEEE 802.6 DQDB standard. SMDS fragmented its datagrams into smaller "cells" for transport, and can be viewed as a technological precursor of ATM.
Increases in raw data rates removed the need for fragmentation into cells, and SMDS' niche market position ensured that it remained a high-priced service. As a result, SMDS has been supplanted by IP-based and Ethernet-based services and MPLS.
Mobile phone
A mobile phone or cellular (cell) phone is an electronic telecommunications device. Most current mobile phones connect to a cellular network of base stations (cell sites), which is in turn interconnected to the public switched telephone network (PSTN) (the exception are satellite phones). Cellular networks were first introduced in the early to mid 1980s (the 1G generation). Prior mobile phones operating without a cellular network (the so-called 0G generation), such as Mobile Telephone Service, date back to 1946. Until the mid to late 1980s, most mobile phones were sufficiently large that they were permanently installed in vehicles as car phones. With the advance of miniaturization, currently the vast majority of mobile phones are handheld. In addition to the standard voice function of a telephone, a mobile phone can support many additional services such as SMS for text messaging, packet switching for access to the Internet, and MMS for sending and receiving photos and video.
SMDS, which stands for Switched Multi-megabit Data Services, was a connectionless service used to connect LANs, MANs and WANs to exchange data. SMDS was based on the IEEE 802.6 DQDB standard. SMDS fragmented its datagrams into smaller "cells" for transport, and can be viewed as a technological precursor of ATM.
Increases in raw data rates removed the need for fragmentation into cells, and SMDS' niche market position ensured that it remained a high-priced service. As a result, SMDS has been supplanted by IP-based and Ethernet-based services and MPLS.
Mobile phone
A mobile phone or cellular (cell) phone is an electronic telecommunications device. Most current mobile phones connect to a cellular network of base stations (cell sites), which is in turn interconnected to the public switched telephone network (PSTN) (the exception are satellite phones). Cellular networks were first introduced in the early to mid 1980s (the 1G generation). Prior mobile phones operating without a cellular network (the so-called 0G generation), such as Mobile Telephone Service, date back to 1946. Until the mid to late 1980s, most mobile phones were sufficiently large that they were permanently installed in vehicles as car phones. With the advance of miniaturization, currently the vast majority of mobile phones are handheld. In addition to the standard voice function of a telephone, a mobile phone can support many additional services such as SMS for text messaging, packet switching for access to the Internet, and MMS for sending and receiving photos and video.
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