IPC Definitions - January 01, 2012

E21B 47/125 - Definition fr

Definition statement

This group covers:

Processes or apparatus in which the transmission link is through the ground.

Informative references

Attention is drawn to the following places, which may be of interest for search:

Magnetic or electric prospecting

G01V 3/00

Electronic transmission systems in which the earth is the medium

H04B 13/02