[RTTY] HAL RVD-1005 docs?

[Ekki Plicht]

Hi list,
out of nostalgic reasons (my father, DJ6XR (sk) used to have one) I bought an 
old HAL RVD-1005 on the Friedrichshafen hamfest.

Does anybody still have such a unit or perhaps the documentation for it? I 
mean, it's pretty straight forward (just two connectors on the back, hi), but 
mine does not work. 
I am using the current loop, fed by a Rohde & Schwarz EK-071 rx which has a 
current loop output. My main question is what kind of current loop the HAL 
expects, +50mA or +-25mA.

tns, 73,
Ekki, df4or