www.DataSheet4U.com ISDN U-BUS Input/Output Transformer TEW6055 TEW6055 is designed to interface with the subscribers premises (NT) and the 2- wire line side of the Central Office Equipment (LT) in the ISDN Network. TEW6055 meets the electrical specifications of ANSI TI.6011988 and the requirements for the Mitel MT8910 DSLIC device. Applications: High performance 2B1Q line code. Up to 50 mA line current. High insulation between line and equipment side. MECHANI.