Windows will not allow two serial communications programs to access
the same serial port at the same time.
There is a trick that you can use however to accomplish the job.
You can use a program from TAL Technologies called TCPCom to
accomplish the job.
TCPCom is basically a RS232 to TCP/IP converter that will open a RS232
port and feed the data that it receives out a TCP/IP port. TCPCom can
also create "Virtual RS232 COM ports" that are actually connections to
a TCP/IP port.
What you would do is to run TCPCom and configure it to open COM1 (the
physical COM port where the device is connected) and then act as a
TCP/IP server.
You would then use TCPCom to create two "Virtual COM ports" (COM3 and
COM4 perhaps) that are connected as TCP/IP clients to the TCP/IP port
that the COM1 port is configured as the TCP/IP server.
You would then open the COM3 and COM4 ports with the two different
serial communications programs and both would be able to send and
receive data in or out the COM1 port.
You can find a demo copy of TCPCom at:
http://www.taltech.com/products/tcpcom.html