SSH ETS 300 103:1990

Integrated Services Digital Network (ISDN); Support of CCITT Recommendation X.21, X.21 bis and X.20 bis based Data Terminal Equipments (DTEs) by an ISDN; Synchronous and asynchronous terminal adaption functions

Scope

(1) The scope of this standard covers the connection of X.21 and X.21bis based terminals of user classes of service 3 to 7 and 19 to the ISDN operating in accordance with circuit-switched or leased circuit services; (2) The scope of this standard also covers the connection of X.20bis based Terminals of CCITT user classes of service 1 and 2, and 19200 bit/s and of asynchronous data rates of 600, 1200, 2400, 3600, 4800, 7200, 9600, 12000, 14400 to the ISDN operating in accordance with circuit-switched or leased circuit services;