With the help of a friend I managed to get my AOR AR8000 receiver and
Optoelectronics OPTOLINK to Trunk and Etrunk using one serial port on the
computer.  Remember Bill Cheek said it had to be done with two or three
ports or with two computers.  Anyway, while building the two level FSK
decoder, solder additional wires to the ground and transmit pins of the
DB-9 connector leading to the computer and run them to a male DB-9
connector which connects to the back of the OPTOLINK.  My AOR is moded with
a phono plug for the Optoelectronics SCOUT, so instead of using the
supplied flat cable (which did not work) I connected the phono plug to the
Half Duplex plug "A" on the front of the OPTOLINK.  All four dip switches
on the back of the OPTOLINK should be in the down position.  Also in the
AOR, the RS232 parameter has to be set to "CR" in the configuration menu. 
This is accessed in the "EXPERT" mode as stated on page 101 of the AOR
manual.   The AOR now acts as the second scanner and follows the talkgroup
frequencies which appear on the computer screen.  PFM!