Installation guide

Making External Connections to Cisco 4000 Series Routers 4-71
Network Connection Considerations
If the network processor module is operating as DTE in NRZI mode, the sense of the
dte-invert-timing command must be manually changed. For instance, if the command
no dte-invert-timing was previously entered in the configuration file, then
dte-invert-timing must be configured for the module to operate as DTE in NRZI mode.
To set the jumpers for NRZI, move the jumpers to the position shown in Figure 4-23 using
the orientation shown in Figure 4-22.
Figure 4-23 Dual Serial Network Processor Module Jumpers, J4 and J5—NRZI
Setting
You must use a special serial cable to connect the router to a modem, CSU/DSU, or other
device as shown in Figure 4-24. This cable, available from your customer service
representative, is normally ordered with the system. See the appendix, “Cabling
Specifications for Cisco 4000 Series Routers,” for more information. Nine different serial
cables are available for the two versions of serial modules: both DTE and DCE versions of
V.35, EIA/TIA-232, EIA/TIA-449, and X.21; and EIA-530 DTE. Note that the cables for
the two versions are not interchangeable.
Port 1
Port 0
J5
J4
Pin 1
H1125a