The Line Sharing Verification Test Set is (LSVT) is intended to verify the DSL portion of a Line Sharing circuit in the Central Office environment.
Data Sheet

LSVT1
Line Sharing Verification Test set: consists of a LSVT2, LSVCD3, LSVC4 and LSVC5
LSVD3
Line Sharing Verification Detector
LSVC4
Test Cord for LSV Transmitter, 3 ft., RJ45 to 5-pin Module
LSVC5
Test Cord for LSV Transmitter, 3 ft., RJ45 to 2 test leads with alligator clips