[GreenKeys] FRXD tape unit

[Duncan Brown]

I came across some old (1945) Teletype Corp. Bulletins  while I was at 
the AWA Museum today.  I thought it was just a M14 RO unit (in typing 
and non-typing variations), but then I realized the bulletins were 
labeled "Reperforator Transmitter Distributor". I took another look for 
a "Transmitter Distributor", but didn't see one.

So I had to actually READ the manual and it turns out this "M14RO" also 
included a tape reader that could read up to the last character punched 
in the tape.

What was the FRDX-3, -4 used for? A regenerative repeater?  How was it a 
better repeater than a polar relay?

Thanks,

Duncan