Panel Mounted Coupler, RJ11 (6x4) JAXX has redesigned the traditional modular coupler by adding grooves that allow the use of retainers so the coupler snap-fits into a rectangular hole. It’s now possible to connect two similar modular cables on each side of a panel. Maximum panel thickness is .075"". Wiring is straight-through for low speed data communication use. Two retainers (order separately) are required to mount one coupler.