Type numbering systems

1. Various European type numbering before 1934
  1A. Cossor
  1B. British Army
  1C. Loewe
  1D. Philips
  1E. TeKaDe
  1F. Telefunken
  1G. Tungsram
2. European type numbering from 1934 and to the end 
3. Type designation system for European industrial tubes
4. US numbering system Note:
dir.  - means directly heated cathode, i.e. a filament.
ind. -  means indirectly heated cathode.

1A. Cossor
Cossor had at least two different systems running in parallell.
System 1: ex. 410HF = 4-10-HF
First digit Second digit(s) Letters
2 = 2 V heater Heater current (sometimes) B = duodiode
4 = 4 V heater   BU = rectifier
    DD = duodiode
    DDT = duodiode-triode
    Det = detector
    DG = tetrode
    GP = triode
    HF = triode
    HL = triode
    HPT = power pentode
    LF = triode
    OT = power pentode
    P = power triode or pentode
    PA = power pentode
    PG = octode
    PT = power pentode
    QD = power pentode
    RC = triode
    SG = tetrode
    SPG = octode
    SPT = pentode
    SU = rectifier
    VPT = pentode
    VS = power pentode
    VSG = power pentode
    XP = power triode
System 2: ex. 41MDG
Digits
= heater
Letters
2 = 4 V dir DDT, DHA  = diode-triode
4 = 4 V dir MCR = triode
13 = 13 V ind. MDG = tetrode
40 = 30 V ind. MH, MHF = triode
41 = 4 V ind. MHL, MLH = triode
42 = 4 V ind. MP = triode
44 = 4 V ind. MPG = octode
  MSG = tetrode
  MVSG = tetrode
  PGA = octode
  STH = triode-hexode
  SU, SUA = rectifier
1B. British Army
 They had several systems, here is an early one:
ARDD1, ARTP2
AR = Army Receiver, Digits = serial number
ARD Diode
ARDD Duo-diode
ARH Heptode
ARP Pentode
ARS Tetrode
ARTH Triode-hexode
ARTP Triode-pentode
AT Transmitting triode
ATP Transmitting pentode
ATS Transmitting tetrode
AU Rectifier
AW Stabilizer
AW Tuning indicator
 
1C. Loewe
 Loewe had also several systems, here is one of them:
4V1
Last digit is serial number
Heater Systems
4 = 4 V D = duodiode
6 =  6 V E = power pentode
13 = 13 V F = pentode
24 = 24 V H = pentode or hexode
33 = 33 V M = mixer
44 = 44 V V = duodiod-triode
  W = duodiod-pentode
 
1D. Philips
Philips had (at least) two different numbering systems, one for
receiving tubes and one for transmitting tubes.

Receiving tubes : B405, C243, E447 etc.
Heater current Heater voltage System
A = 60-100 mA 1 = 1 V 04-40 = triodes
B = 100-200mA 2 = 2 V 41, 51 = space charge tetrodes
C = 200-400 mA 3 = 3 V 42, 52, 62 = tetrodes
D = 400-700mA 4 = 4 V 43, 53, 63 = power pentodes
E = 0,7-1,25 A 5 = 5V 44, 54 = tetrode-diodes
F = > 1,25 A 6 = 6V 45, 55 = variable tetrodes
. 20 = 20 V 46, 56 = pentodes
. . 47, 57 = variable pentodes
. . 48, 58 = mixer hexodes
. . 49, 59 = variable hexodes
. . 60, 99 = triodes
Transmitting tubes: MC1/50, QQE06/40, TAW12/50
System  Cathode Anode voltage Anode dissipation
M = LF triode A = tungsten 02 = 200 V 12 = 12 W (below 1 kV Va)
P = pentode B = thoriated tungsten 03 = 300 V 40 = 40 W (below 1 kV Va)
Q = tetrode C = oxide 1 = 1 kV 10 = 10 kW
QQ = duo-tetrode E = indirectly heated  12 = 12 kV .
T = HF-triode . . .
 
1E. TeKaDe
2L20, 3G15, 4K60
Digit-Letter-Digits
Filament/Heater System Various
1 = 1,0 V A = audiontriode 06 = 60 mA fil.
2 = 2,0 V B = triode 30 = 300 mA heater
3 = 2,5/3,0 V C = triode 100 = 1,0 A heater
4 = 4,0/4,5 V CC = duo-triode -
6 = 6,3 V D, DA = space charge tube -
8 = 8 V E, F = pentode -
13 = 13 V G, GG = rectifier -
20 = 20 V H = triode
HA = duo-triode
-
200 = 200 mA K = power triode -
- L = audio output tube -
- N = triode -
- P = power pentode -
- S = tetrode -
- U = universal triode -
- W = resistance couple
amplifier triode
-
- Y = rectifier -
- Z = rectifier -
1F. Telefunken
REN914, RENS1819, RES374d, REZ364
to be interpreted as:
REN-9-1-4, RENS-18-19, RES-3-7-4-d, REZ-3-6-4
System type Heater
(approx)
Serial
number
Heater Suffix
RE = receiving tube, dir. 0 = <100mA 1-19 2 = 2,0 V bi =bifilar heater
REN = receiving triode, ind 1 = 100-150 mA . 4 = 4,0 V d = space charge
RES = tetrode, dir. 2 = 200 mA . 5 = 5,0 V s = for serial heater
RENS = tetrode, ind. 3 = 300 mA . 6 = 6,0 V t = old base
REZ = duo-triode, dir. 4 = various . . w = two side conn.
RENZ = duo-triode, ind. 5 = 500 mA . . .
RFG = rectifier for TV 6 = 600-650 mA . . .
RG = HV rectifier 9 = 900-1200 mA . . .
RGL = battery rectifier 12 = 1,0-1,2 A . . .
RGN = mains rectifier 13 = 1,1-1,3 A . . .
RGQZ = gas filled rectifier 18 = 180 mA serial . . .
RS = transmitting tube . . . .
RSQ = grid controlled rectifier . . . .
RGQ = gas filled rectifier . . . .
1G. Tungsram
Tungsram used to put  the letter T in front of the standard European type number, AL1 thus became TAL1 etc.
The following system was also used:
P614 , G409, PV 4 100, 
A = special power tubes Heater in volts Heater current
BR = voltage stabilizers 4 = 4,0 V 05 = 50 mA
CB = duo-triodes 6 = 6,3 V 10 = 100 mA
D = audion detectors . 15 = 150 mA
DDT = triode-diodes . etc
DG = tetrodes . 100 = 1 A
DS = diode-tetrodes . .
FH = variable hexodes . .
G = preamplifiers . .
H = HF-triodes . .
HD = LF- triodes . .
HH = hexodes . .
HL = preamplifiers . .
HP = pentodes . .
HR = dir. heated  triodes . .
L = power triodes . .
ME = tuning indicators . .
MH = mixers . .
O = oscillator and transmitting tubes . .
P = power triodes . .
PP = power pentodes . .
PV, PVB, PVX = full wave rectifiers . .
R = resistance coupled amplifiers . .
S, SE = tetrodes . .
V, VEG = rectifiers . .
2.European type numbering system from 1934
AC2, DAC21, EABC80, HM34, PL802, UCH81 etc. 

The type designation consists of: Two or more letters followed by one or more digits.
First letter indicates the heater voltage or current
Second and subsequent letters indicate the construction and/or application of the tube.
The digits indicates the type of base.
First letter Meaning Notes
A 4 Volt indirectly heated Exception RFT AL860 which has 2,4/4,8V
B 180mA filament  
C 200mA filament  
D 1,4 V filament Sometimes 0,5-1,25 V
E 6,3 V indirectly heated  
F 12,6 V indirectly heated Only known types: FL152, FZ1
G 5 V indirectly heated  
H 12,6 V indirectly heated Sometimes 150mA
I 20 V indirectly heated Only known types: RFT  IF860 and IL861
K 2 V filament Except KT66 etc where KT means Kinkless Tetrode.
L 450 mA indirectly heated  
O 150 mA Only used for an octal range
P 300 mA indirectly heated  
T Misc. Only known type Mullard TY86F
U 100 mA indirectly heated  
V 50 mA indirectly heated  
X 600 mA indirectly heated  
Y 450 mA indirectly heated  
Subsequent letter(s) Function Notes
A Signal diode Except EA111 which is a booster diode.
B Double signal diode with common cathode  
C Triode (excl. power triode) EC360 and ECC230 are power triodes.
D Power triode  
E Tetrode (excl. power tetrode) Ediswan EE80 is a beam power tetrode.
F Beam tetrode or pentode (excl. power pentode) Except EF8 and EF38 which are hexodes
H Hexode or heptode  
K Octode or heptode  
L Power beam tetrode or pentode  
M Tuning indicator Except EM83/UM83 which have dual systems.
N Thyratron  
P Secondary emission Inconsistently used
Q Enneode (Nonode)  
S TV sync oscillator Only know type Telefunken ES111
T Beam deflection tube Only known types: E1T, E80T, ET51
W Gas filled rectifier Only known type: Philips EW60
X Gas filled full wave rectifier Only known types: AX1, AX50
Y Half wave rectifier CY2 has dual systems
Z Full wave rectifier  
Following digits:  Base and (examples).
1-10 P5, P8, Octal
11-19 G8A
20-29 Lock-in B8G. For the battery range DAC21-DM21 octal base
30-39 Octal  IO
40-49 Rimlock  B8A, with W-suffix special base for Wehrmacht (e.g. DCH41W)
50-59 Miscellaneous: B9G (EF50), B8G (EF51), P8 (EL50), Octal (DAH50, EC56), 3-pin glass (EA50, EC53), Disc-seal (EA52, EC55), German 10-pin (UEL51), miniature 4-pin (DF51), B26A (ET51), B9D (E55L).
60-69 Miscellaneous: B9G (EFP60), British pin base (AL60), flat-wire-ended subminiature.
70-79 B8G (EM71, EM72), round wire-ended subminiature.
80-89 Noval  B9A
90-99 Miniature B7G
100-109 Miniature B7G (DLL101), Wehrmacht base (AF100), German PTT base (AC100), European pin (AD101).
110-119 Y-base (EA111), B8A (ECL113)
130-139 Octal
150-159 German 10-pin (EL156), 10-pin all-glass, one large pin (EL152), octal (EC157)
160-169 Flat wire-ended subminiature, German Y-base (EC162)
170-179 RFT 8-pin like loctal with metal spigot but no shell (EF172), RFT 11-pin all-glass with one pin offset (EL173)
180-189 Noval  B9A
190-199 Miniature B7G
200-209 Decal B10B (PCF200)
230-239 Octal
270-279 RFT 11-pin all-glass with one pin offset (EA271, UA271)
280-289 Noval  B9A
300-399 Octal
400-499 Rimlock B8A (EF410)
500-529 Magnoval B9D (PL519 etc), Novar (only known EL520)
600-699 Flat wire-ended
700-799 Round wire-ended
800-899 Noval  B9A
900-999 Miniature B7G
1000-1999 Round wire-ended (EC1000), special nuvistor (EC1010)
2000-2999 Decal B10B (ECC2000)
3000-3999 Octal (EL3010)
5000 Magnoval B9D (EL5000)
8000 Noval  B9A
The information above has come from many different sources of which I would like to especially mention an article by Alan Blake, published in Tube Collector vol.2, No. 2

3. Type designation system for European industrial tubes

E130L, E283CC, E91AA
Industrial and long life versions have often reversed the order of the groups compared to the system above. ECC83 in long life version thus becomes E83CC

XQ1032, YH1110, ZM1020
Other industrial tubes designations consists of:
Two letters followed by a serial number.

First letter indicates category 
X Tubes employing photosensitive materials (except XM1000)
Y Vacuum tubes for transmitting, microwave or industrial applications
Z Gas filled tubes (except category X)
Second letter indicates construction
A Diode
C Trigger tube
D Triode (including double diodes)
G Miscellaneous
H Traveling wave tube
J Magnetron
K Klystron
L Tetrode or pentode (including double tetrode or pentode)
M Cold cathode indicator or counter tube (except XM1000 which has a filament)
P Photo multiplier tube or radiation counter tube.
Q Camera tube
T Thyratron
X Ignitron, image intensifier or image converter
Y Rectifier
Z Voltage stabilizer
4. US type numbering system
1A3, 6BQ5, 12AU7, 25L6GT
First group of digits indicates the approximate filament/heater voltage
The letters that follow acts as a serial number
The second group of digits (mostly only one digit) indicates how many electrodes that are connected to the base.
The last group of letters indicates the bulb type.
CRTs usually ends with Pxx where xx indicates the type of phosphor. P4 is standard B/W television, P22 is color-TV type and P31 is for oscilloscope, just to mention a few.