Transmitter-capsules, dimensions and characteristics?

[dsk]

What you use to see is normal, all others are odd!

Not very many US telephones her, but their transmitters has small dimensions:
WE 500/2500:  Ø=46mm height=14.5 mm
Most Norwegian transmitters: (Elektisk Bureau or EB) are huge:
EB 1934...1967  Ø=55mm H=19mm   
The majority of European phones I have seen uses Ø=48mm H= 15 to 21mm

Not easy to deem the impedance, but it seems like the Norwegians are 50 ohms, and most others are 200 ohms.

Someone out there who could help with some systematic info?

dsk

[dsk]

Some pictures will make this clearer, I hope  

dsk