No special cable required. A SpeakerLink (SL) cable carries the digital signal (L+R) from the 218 to the SL input on the G65.

Brian

Main: G65, MD600 Sooloos, MC200 Roon Core, MS600, 210, 218, UHD722, DSP5200SE, DSP5200HCSE, M6 & DSW.2
System 2: AC200 MS200, WiiM Pro+, M6.
Other: DSP5000 (96/24v1), DSP3300.