First, you asked for advanced codes, and the site will provide those, and the 7960 of course doesn't require JP1 to enter them.  So you can get most discretes without an interface cable.  Just enter the EFC manually.

Also, I think you mis-estimate the currrent capability of JP1 with respect to the 7960.  Certainly for the purpose of generating discrete codes to send to another (less capable ) remote, the JP1 support is way more than adequate.