caseman9191,
I have a 1985 Bridgeport Series 1 R2E4 with boss 9 and can drip feed no problem running win XP and EZ-Link. Works like a charm.
I am using port B. Port A I could not get working at all. I dont use this machine anymore since I got my VMC converted to Linuxcnc.
Let me know if you need pinouts and baudrates and stuff. I could power it back up and check.
Bob