Switched Voice Service or Switched Long Distance is commonly referred to as the Plain Old Telephone Service (POTS), the traditional access method used by small organizations, though it also entails any line types connecting directly to the local phone company. With Switched Service, your local telephone company provides copper lines that carry local, long distance and toll-free (800) calling.
-as quoted from CDW website
Switched Voice Service or Switched Long Distance is a term describing regular local or long distance phone service that is "switched" or run through the local central office. All residential and many business services are switched services. Unlike "private line" service, where lines carrying only one customer's phone traffic run between two points, switched service is carried on the public telephone network.
-as quoted from IDT website
Note: Switched service is the traditional service that residential customers on a day to day basis. eg. a regular phone line in your home.