Not all command line switches are optional.
While most of the command line switches described in Utility Guide > start_iq Database Server Startup Utility are optional, you must specify the -n switch to run SAP Sybase IQ effectively.
If you use TCP/IP to connect to the server, include network connection parameters as well. If you start the server without the parameter -x 'tcpip(port=nnnn)', the server uses the default TCP/IP port number, 2638. If you specify a port number that is already in use, the server fails to start.