Digital Phone Adapter Kit for the SO-24A. Viking now offers modular cords and adapters to simplify wiring when using the Viking SO-24A with digital telephones that operate on only one pair. These modular cords and adapters provide easy installation and a neat appearance to the user. The custom split cord is 25 feet long but can be shortened if desired. The new 5 inch version of the handset splitter is long enough to reach the handset jack of nearly any digital phone.