Remember the first transistor radio? Last Monday, Oct. 18, marked the 50th anniversary of the Regency TR-1, the first transistor radio. The radio used four germanium transistors and operated on a 22.5-V battery. It cost $49.95. For information on the Regency TR-1 and links to other Web sites with information on early transistor radios, see www.regencytr1.com. For commentary on the anniversary, a look at how technology has progressed and where it might be headed, see Rupert Goodwin's commentary We're fifty years into the future.