Welltech ePBX80 V.1.1 - Manual (Page 121)

Welltech Technology Co., Ltd. 121
Figure 3
Step 4: move the cursor to secondary peak. And you can see the high frequency
on red block. (See figure 4)
Figure 4
Step 5: Enter two values on Freq 1 and Freq 2 at disconnect 1. (See figure 5)