Datasheet

Installing 2T16S Network Processor Modules in the Cisco 4000 Series

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The data rate depends on the type of electrical interface used. EIA/TIA-232 only supports speeds up to

64 kbps; X.21, V.35, EIA/TIA-449, or EIA-530A support higher speeds. Note that EIA/TIA-449 or

EIA-530A interfaces are only supported on the high-speed serial ports.

When connecting serial devices, consider the adapter cables as an extension of the router for external

connections. Therefore, use DTE cables to connect the router to remote DCE devices such as modems

or DSUs, and use DCE cables to connect the router to remote DTE devices such as a host, PC, or another

router.

Serial Distance Limitations

Serial signals can travel a limited distance at any given bit rate; generally, the slower the transmission

(baud) rate, the greater the distance. All serial signals are subject to distance limits, beyond which a

signal degrades significantly or is completely lost. Table 3 lists the recommended maximum speeds and

distances for each serial interface type from the IEEE specification; however, you might get good results

at speeds and distances greater than those listed. If you understand the electrical problems that might

arise and can compensate for them, you can get good results with rates and distances greater than those

shown. However, do so at your own risk.

Balanced drivers allow EIA/TIA-449 signals to travel greater distances than EIA/TIA-232 signals. The

recommended distance limits for EIA/TIA-449 shown in Table 3 are also valid for V.35, X.21, and

EIA-530A. However, you can get good results at distances and rates greater than those shown in Table 3.

Typically, EIA/TIA-449 and EIA/530A support 2-Mbps rates, and V.35 can support 4-Mbps rates

(2-Mbps in the 2T16S network processor module).

High-Speed Serial Cables

This section describes the high-speed cable connectors. For pinout descriptions, see the section “Cabling

Specifications” in the Cisco 4000 Series Installation Guide. Although the printed manual ships with your

router, the most current version appears on the on the World Wide Web at http://www.cisco.com and

on the Documentation CD that ships with your router.

Table 4 IEEE Standard Transmission Speed Versus Distance

Data Rate EIA/TIA-232 Distances

EIA/TIA-449, EIA-530A,

X.21, and V.35 Distances

Bits per Second Feet Meters Feet Meters

2400 200 60 4100 1250

4800 100 30 2050 625

9600 50 15 1025 312

19200 25 7.6 513 156

38400 12 3.7 256 78

56000 8.6 2.6 102 31

1544000 (T1) N/A N/A 50 15