The Wandel & Goltermann IBT10 is a special ISDN-D Channel Test Set for the so-called D-Channel (Protocol Channel). For measurement and troubleshooting you should be able to interprete the D-channel protocol. The following protocols are available with the Wandel & Goltermann D - Channel Tester: EDSS-1, 1TR6, VN 3, VN 4, V 1 Swissnet 2, BTNR 191, TPH 1962, NTT, Q.931, Telenokia, Televerket, 1TR67, all this in english, french or german language. Measurement modes: telephone mode, bit error ratio (BERT), fixed mode (G.821 evaluation), protocol analysis, NT-simulation, demo mode. Connectors: TAE, Mini-DIN, RJ-45, RJ-11. Battery operation (1,5 V).