Adam Clark accepted answer staff Oct. 9, 2013, 3:32 p.m.
The Channel Code is a 3-character code that specifies the type, bandwidth of the recorded signal, and orientation of the sensor. For instance, a channel code of
BHZ is used to indicate the signal came from a broadband
B, high gain seismometer
H and is recording ground motion in the vertical
A complete summary of channel codes can be found in Appendix A of the FDSN SEED Manual
You may also like to try the Data Channel Wizard.