[GreenKeys] Teletype 3320

[Nico de Jong]

Hello fellow greenkeyers

For the danish IT museum, I need to connect a Teletype ASR 3320 to a 
comport, so we can simulate the old european Gentex network.
This 3320 has probably been connected to a PDP mini or similar.
There connecting cable uses 5 pins : 2, 3 and 7, which is straightforward, 
plus 24 and 25.
My questions are :
- what could 24 and 25 have been used for
- is this a straight RS232 machine, or do I need a 20 mA current source

All the best

Nico (ex dutch ptt, 31068 RA GV NL)