This Rock-ola cable assembly came from one of the Capri or Rhapsody models that I parted out years ago.
One end connects to the Write-In Unit Assembly in models that use this type of connector (they used two types that I have seen).
I do not recall where the other end goes.

Each connector has 3 contacts and the cable measures about 72 inches in length.
(183 cm).

It is in good condition and ready to use.