Specifications
to scan and test the required pair of line fastlyamong the numerous lines.
scaning feature: to test fastly the opening or sh
among the numerous lines.
scaning feature: to test fastly the opening or short circuit and the sequence of line
to test the circuit status:
A).to test the direct-current level and determine the positive or negative polarity.
B).to test the ring-current signal.
C).to test the opening or short circuit in line.
