Cisco 2500 Series Installation And Configuration Manual page 35

Installing the Router
Step 4 Connect one end of each asynchronous/synchronous cable to the asynchronous/synchronous ports
(labeled Serial n (A/S)), and then connect the other end to a CSU/DSU or asynchronous device. (See
Figure 3-14.)
For asynchronous/synchronous port pinouts, refer to the appendix
Figure 3-14: Connecting Asynchronous Serial Cables
Step 5 Connect the ISDN BRI port (RJ-45) to an NT1 device. (See
Figure 3-15: Connecting the ISDN BRI Port to an NT1 Device
http://www.cisco.com/univercd/cc/td/doc/product/access/acs_fix/cis2500/2520/2520_23/c2520ins.htm (11 of 14) [10/27/2000 3:07:47 PM]
"Cable Specifications."
Figure 3-15)