Hi John,
It's not possible with only the RRC's connected.
btw its Mode=1 you have to select if you give up com2,
An easy workaround is to use a Tibbo DS203 1 Serial device server +/-120 Euro
(probably bad luck but the first 2 I had were broken)
or more reliable MOXA Nport 5210 who has 2 serials via ethernet at 189 Euro
Both can do TXD,RXD,RTS,CTS,DTR,DSR,DCD,GND.
Port 1 can be for amp or rotator and port 2 for rtty-cw or even control antennas,
switching antenna directions K9AY etc
Guy ON4AOI