-
Regency TR-1
The Regency TR-1 was the first commercially manufactured transistor radio. First sold in 1954, it was a novelty due to small size and portability; about 150,000 units were sold despite mediocre performance. The device demonstrated the use of transistors for consumer electronics; previously transistors had only been used in military or industrial applications. Surviving specimens are sought out by collectors. -
Raytheon 8-TP-1
In February 1955 the second transistor radio, the 8-TP-1, was introduced by Raytheon. It was a larger portable transistor radio, including an expansive four-inch speaker and four additional transistors (the TR-1 used only four). As a result, the sound quality was much better than the TR-1. An additional benefit of the 8-TP-1 was its efficient battery consumption. -
Stereobelt
The Stereobelt was the first portable personal stereo audio cassette player. It was invented by the German-Brazilian Andreas Pavel. The Stereobelt was the ancestor of the Walkman and modern-day personal audio devices such as the Zune and the iPod. -
Walkman
The original Walkman actually introduced a change in music listening habits by allowing people to carry recorded music with them and listen to music through lightweight headphones. Owners of the Walkman were able to take back their "lost" time, commuting for example, and turn it into a pleasurable experience, or add a soundtrack to their urban surroundings. -
Discman
Discman was the product name given to Sony's first portable CD player, the D-5 (North America and various other countries)/D-50, which was the first on the market in 1984, and adopted for Sony's entire portable CD player line. In Japan, all Discman products are referred to as "CD Walkman" and the name was adopted worldwide in 2000 along with a redesigned "Walkman" logo. -
MiniDisc
The MiniDisc (MD) is a magneto-optical disc-based data storage device offering a capacity of 74 minutes and, later, 80 minutes, of digitized audio or 1 gigabyte of Hi-MD data. -
MPMan
The internal flash memory could be expanded, but there was no support for external memory. It was delivered with a docking station. To put music into the device, the music first had to be encoded in the mp3 format by an encoder provided by the user, and then transferred via the parallel port to the docking station that connected to the portable player device. -
Period: to
iPod
After the MPMAN started the iPod age
from Oct,23 2001 up to day
See the picture here: https://upload.wikimedia.org/wikipedia/commons/thumb/9/9b/IPod_line_as_of_2014.png/300px-IPod_line_as_of_2014.png
