This site contains resources and links to help those working with vacuum tubes / thermionic valves - historic information and data
Early valve manufacturer history - THE ORIGINS OF SIEMENS UK, SIEMENS & HALSKE, TELEFUNKEN, OSRAM (AND SVETLANA) is here. , also Raytheon origins
If you need tube/ valve data sheets, Frank's data pages are probably the most comprehensive collection on the www.
This short list of EIA codes is intended to facilitate identification of thermionic valves (aka electron tubes) used for audio purposes.
The EIA codes are a supplier identification system used for all electronic parts made by members of the Electronics Industry Alliance of America (previously known as the Electronic Industries Association, before that, RETMA, Radio, Electronics and Television Manufacturers Association, and before that, RMA, the Radio Manufacturer's Association). .
There are often date codes applied at the same time, which can be useful. For example, comparing the codes on parts inside old Fender amplifiers allows people to assign a date of manufacture for the amplifier.
Where date codes are used, they may be combined into a 6 or 7 character block with the EIA code. The EIA code should be the first three characters, the last two characters are the week number, the remaining one or two numbers in the middle indicate the year. On valves, the EIA code is usually shown separately from the date code.
For valve identification purposes, the codes can be useful to identify an original supplier when a valve has been branded for OEM sales purposes, eg. for an organ manufacturer or a radio manufacturer. It is not always a reliable indicator, as there are instances where an EIA code has been used on imported valves , and in some cases the EIA code is not applied (RCA hardly ever used the code on their noval types, for example).
162 Eimac (Eitel-McCullough, Inc)
169 Electronic Tube Corp
188 General Electric (GE Ken-Rad) 
247 National Union
336 Western Electric
423 Philips ECG
713 Taylor, Cetron-Taylor, Cetronics
722 Sylvania OEM sales, eg. Baldwin, Beckman labels
738 Lewis and Kaufman, Heintz and Kaufman
749 National (later Cetron)
1022 Fisher 
1109 Raytheon (far east supply)
 Fisher used their EIA code (1022) on tubes they labelled themselves, whatever the source - usually Telefunken or Philips group, although the <> mark gives away the Telefunkens, and the Philips codes give away the Mullards, Philips, S&H and Amperex.
 It is not true that RCA never bought in valves from other makers - but when RCA did buy valves in, it was usually from Philips group. Sometimes you find RCA valves with 274, and a Philips code - as with Fisher, the 274 shows who did the labelling.
[3}Often with a plant indicator number, eg. codes 188-1, 188-2, 188-3, 188-4, 188-5 indicate manufacture at the plants around Kentucky.
Other Useful Marks - H02 on Raytheon (Japan), USA 3 etched on some Tung-Sol. Type number etched in a rectangular box is typical of Tung-Sol. Type number etched in a box with "stop sign" corners is typical of RCA, but also used by National (Japan production).
Much more info on hifi and instrument amp audio valves and tubes coming soon!