woshizhu,
There has been an existing discussion on RS-485, however the SPICE model evolves from an IBIS model. What this means is that usually IBIS is good at showing you digital transition and loading data, but will not likely get you a functional SPICE model that you are looking for. Here is the previous thread.
http://forums.ni.com/ni/board/message?board.id=370&thread.id=844
However, RS-485 transceivers are relatively simple in that they convert single ended signals to differential and have speed and loading specifications that would allow one to create a basic functional model. As a starting point, do you have a specific PN in mind, there are several from Maxim (full/half duplex) that might be appropriate choices?
Same question with the infrared communication component - please let us know a Part Number of a typical device you would be looking at.
Regards,
Patrick Noonan
Business Development Manager
National Instruments - Electronics Workbench Group
50 Market St. 1-A
S. Portland, ME 04106
Email: patrick.noonan@ni.com
Tel. (207) 892-9130
Fax. (512) 683-7754
