Basic Butt Set Telephone Line Tester: Dial Tone, Dial Out, Caller ID Functions and More - (BSX200)BSX200 Basic Butt Set is designed for people who occasionally need to deal with dial tone but don't require all of the features of an expensive model. Read More > DESCRIPTION BSX200 Basic Butt Set is designed for people who occasionally need to deal with dial tone but don't require all of the features of an expensive model. The BSX200 provides user with dial tone, dial out, Caller ID, last number redial, on off hangup button, flash button, DTM and FSK