Patent ID: 7158048

Claim:
Apparatus for conducting geophysical surveys, comprising: at least one multi-conductor cable having a plurality of take-out locations; a controller transmitting a coded command signal having a first portion that is modifiable to identify a specific take-out location and a second portion identifying a specific conductor of said cable to be connected to ground at said specific take-out location; and a plurality of interchangeable addressable switches connected in series to said cable at selected ones of said take-out locations, each of said switches being operable to receive and modify the first portion of said command signal and to transmit the command signal so modified to an adjacent one of said switches, wherein upon receipt of a coded command signal, each said switch examines the first portion thereof to determine if said coded command signal is addressed thereto, if not, said switch modifying the first portion and transmitting the modified coded command signal to said adjacent switch and if so, said switch connecting said specific conductor to ground in accordance with said second portion of the coded command signal.