Hi Greg,
Can you be More Specific? What Make and Model is the Spectrum Analyzer? What type of interface does it have?
Most Spectrum Analyzer's will have a GPIB interface. If its very old model.. It may have a Proprietary Parallel Interface.
If you want to Interface your PC Serial Port to GPIB Port on the Instrument - there is one way. Get Following GPIB to RS232 Converter/Controller based on what you want to do. These are available from NI.
NI GPIB-232CV-A
GPIB-to-RS-232 "Converter"
http://sine.ni.com/apps/we/nioc.vp?cid=1831〈=US
or
NI GPIB-232CT-A
GPIB-to-RS-232 "Controller"
http://sine.ni.com/apps/we/nioc.vp?cid=1831〈=US
But Then Why not get a GPIB Card Instead and be done with the whole issue....!!
Good Luck!!
Mache
Good Luck!
Mache