After some experimenting I have two new items running via com1 of the remote-rig boxes (old mark1-model, but should also work with the recent model):
Elecraft WN2-Wattmeter: straight forward rs232-cable at control site, 0-modem-cable at remote(radio)-site
com1-settings: mode 3, 9600 Baud, 1 stop bit, no parity on both boxes
Easy Rotor Control Interface (for details about that excellent and cheap antenna rotor interface see
www.schmidt-alba.de): straight forward rs232-cable at control site, 0-modem-cable at remote(radio)-site, com1-settings: mode 3, 9600 Baud, 1 stop bit, no parity
To explain the basics in a few words:
both of the remote-rig boxes com1 act as dce (data communication equipment). dce and dte (data terminal equipment), e.g. a pc can be connected via straight forward RS-232-cable. To connect a dce to another dce, you need a 0-modem cable (at least pin 2 and 3 crossed). Most "radio amateur toys" like wattmeters, antenna rotors or a lot of transceivers are configured as dce. That's the reason why a straight forward cable is needed at the control site and a 0-modem cable is needed at the remote site.
Finally a working wattmeter to monitor a remote station and a good serial rotor interface for azimuth and elevation!
May be this is of interest for some users, saves hours of trying and soldering different cables
73 and happy remoting de Mark, HB9AZT