YOU CAN IMPROVISE A DOMETIC STYLE COMMUNICATION CABLE BY CUTTING A PHONE EXTENSION CORD AND SPLICING BACK TOGETHER REVERSING THE COLOR PATTERN - THIS CAN BE A BIT DIFFICULT AND SOLDERING WILL HELP

OR YOU CAN PURCHASE TWO EXTENSION CORDS AND CONNECT THEM WITH A PHONE OUTLET DUPLEX ADAPTER. THE ADAPTER WILL PUT BACK IN PROPER POLARITY