Hello again!
I am currently looking for a datasheet / pinout diagram for a Narva "Typ 2" TCXO, see attached photos.
As far as I know these Narva TCXOs were manufactured in the GDR for military purposes (so the sequence 04 83 might well mean this thing was manufactured in 1983).
I figured this would be the best place to ask, considering that there are more than a few people from Germany active on this forum who might be most likely to have information on these.
Thanks,
Elia
EDIT: I have contacted the eBay seller and he pointed me to a piece of kit that used this reference oscillator: the EKD300 built by Funkwerk Köpenick. The schematics (including pinout) can be found here:
http://dl6lim.darc.de/ekd300_e.html