Steve,
Im sorry but I am going to have a rant, it is not directed only at you....
I work in an environment where I have to provide technical support to supposed engineers that know the products they are supporting themselfs. Allmost every time they pose a question there is an issue of context which provokes a returned question rather than an answer as not enough information was provided in the first place.
Now on this forum, I tend to provide help to others (as I will do on this occasion in a bit) but the original question is usually vague and somewhat ambigious so there is usually some two ing anf frowing of questions and answers before the original question can be answered properly.
Please, please, please try and avoid just asking the question without providing some background information, ie what the question relates to, product numbers, manufactures etc.
In this case, Steve, I have to make an educated guess that you refer to the LGB programming software, but of course you could be refering to the Massoth software or DecoderPro!
In any case, to answer the question, here is an extract from the LGB manual:
[align=left]Another alternative is to set COM interface number automatically by defining a special code[/align] [align=left]placed after the LGB program name and one blank::[/align] [align=left]C
rogram FilesLGB_V6MTS-PC.EXE L,1 for COM=1[/align] [align=left]or up to? ..[/align] C
rogram FilesLGB_V6MTS-PC.EXE L,99 for COM=99