TPI 105 - Data Test Unit with DS1, DSO, 4WLL interfaces.

TPI 108/109RT Data Test Unit.

TPI 108/109RTII Data Test Unit.

TPI 546 ISDN "U" Monitor / Analyzer.

TPI 550B ISDN Basic Rate Portable Test Set with accessories

TPI 550B+ AKA TPI-550. ISDN BRI test set with U Monitor and Data/Bert options

TPI 550B+ AKA TPI-550. ISDN BRI test set with EBS / POTS & 2B1Q Interfaces

TPI 550B+ AKA TPI-550. ISDN BRI test set with Data/BERT, NI1 Call Control, ViTL, 2B1Q & UMON.

TPI 550B+ AKA TPI-550. ISDN BRI test set. Various option packages available starting at $335.

TPI 550B AKA TPI-550 ISDN BRI test set with options 2B1Q, Mon, UMon interfaces plus data bert & VITL (PC software not included)

TPI 550B+ AKA TPI-550. ISDN BRI test set with 2B1Q interface, Data Bert option, & NI1 Call Control

TPI 550B+ AKA TPI-550. ISDN BRI test set with options 2B1Q interface, Data Bert option, and VITL Option (PC software not included)

TPI 550B+ AKA TPI-550. ISDN BRI test set with Data/BERT, NI1 Call Control, ViTL, 2B1Q, UMON & Monitor

TPI 570 - PRI ISDN test set.

TPI 570 - PRI ISDN test set. With BRI option. Tests both PRI and BRI

TPI 570LCL-1 - Load coil detector for TPI 570.

TPI 95 Digital Loop Analyzer.