I have the manual for the MPC-1000C II E-Series.
Besides the typical 60 Ma Loop it has 3 diferent FSK outputs at the rear
panel:
1) EIA RS-232C Mark -12V and Space +12V
2) MIL STD 188C Mark +6V and Space -6V
3) Regen FSK Mark +12V and Space -12V
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