ISDN Primary Rate Test Set The Leader in Portable ISDN Testing The first portable test set to support Primary Rate Interface ISDN, TTC s TPI 570 has now become the industry standard in Primary (PRI) and Basic Rate (BRI) ISDN testing.
ISDN Primary Rate Test Set The Leader in Portable ISDN Testing The first portable test set to support Primary Rate Interface ISDN, TTC s TPI 570 has now become the industry standard in Primary (PRI) and Basic Rate (BRI) ISDN testing. Most major ISDN service providers, including all versatility and power. A full-featured, multi-functional test set, the TPI 570 supports all U.S. call controls, including national ISDN, and allows considerable flexibility in turning-up and troubleshooting present and future PRI and BRI ISDN services.