Cisco High-Speed - Expansion module - HWIC - RS-232, RS-530, X.21, V.35, RS-449, RS-530A - 2 ports - for Cisco 1841, 1841 ADSL2, 1921 4-pair, 1921 ADSL2+, 1921 T1, 19XX, 28XX, 29XX, 38XX, 39XX

Dial access server. Asynchronous HWICs can connect to external dial modems to provide low-density dial access servers. Legacy protocol transport. Serial and synchronous/asynchronous ports are ideally suited to transport legacy traffic across a TCP/IP network, facilitating network convergence and eliminating costly separate leased lines for this traffic.