Connecting Si-Tex Sp-70 Autopilot to E97

Hi, my new (used) Tiara came with an E97 MFD and a Si-Tex Sp-70 autopilot, I understand these can be connected together via NMEA.

My questions are:

1. Where do I get this cable?
2. What will it do for me? Will the Waypoints I enter be sent to the Autopilot so it follows them?

Thanks.