Racal MA4258B Voice Scrambler Sp/Mic

[Batman]

Any info on these?

Schematics, Manuals, Connector Pin Out, Etc.

What is the Fill (1/16" TRS) Jack?

There is also a unmarked 1/8" TRS jack any ideas?

there is a 4 position switch on top what is it for?

These are Very Heavy and well built.

also what is the encryption type rolling inversion, fixed inversion or DES? i'm assuming it is not DES though as i believe DES requires being tapped before de emphasis to operate properly?

Can these be used in modes other than FM? such as AM or SSB?

here is the auction i won with pic's of the mic's
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... K:MEWNX:IT