22 Nortel Secure Router 2330/4134 hardware components fundamentalsATTENTIONSlot 2 of the Secure Router 4134 supports only one port of any WAN data SmallModule. If you install a 2-port Small Module in Slot 2, and use the Small Modulefor data connections, one port only is functional (port 1).This limitation also applies to the 2-port T1/E1 and ISDN BRI Small Modules ifthey are configured for voice traffic: only port 2/1 is functional. This limitationdoes not apply to FXS or FXO voice modules.This limitation does not apply to the Secure Router 2330.The following figures show the two types of T1/E1 Small Modules.Figure 41-port T1/E1 Small ModuleFigure 52-port T1/E1 Small ModuleIn data mode, the 1-port T1/E1 Small Module provides either one T1 port(supports 24 timeslots with a line data rate of 1.544 Mbps) or one E1 port(supports 31 timeslots with a line data rate of 2.048 Mbps).In voice mode, the T1/E1 Small Module supports Channel AssociatedSignaling (CAS) to provide the Secure Router 2330/4134 with connectionsto the Public Switched Telephone Network (PSTN).You can also configure the 1- and 2-port T1/E1 Small Modules to operateas Integrated Services Digital Network (ISDN) primary rate interface (PRI)connections, providing 23 (T1) or 30 (E1) bearer channels (B-channel) fordata and 1 D-channel for signaling.The 2-port T1/E1 Small Module provides either two T1 ports or two E1ports.Nortel Secure Router 2330/4134Installation — Hardware ComponentsNN47263-301 03.01 7 September 2009Copyright © 2007-2008 Nortel Networks. All Rights Reserved.