Cisco Systems 3700 Series ISDN BRI Connections, Asynchronous/Synchronous Serial Module Data Rates

Chapter 2 Preparing to Install the Router

Preparing to Connect to a Network

Table 2-3 Serial Signal Transmission Speeds and Distances

	EIA/TIA-232		EIA/TIA-449, X.21, V.35,
	Distance		EIA-530 Distance
Rate (bps)	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)	—	—	50	15

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 2-3are also valid for V.35, X.21, and EIA-530. Typically, EIA/TIA-449 and EIA-530 can support 2-Mbps rates, and V.35 can support 4-Mbps rates.

Asynchronous/Synchronous Serial Module Data Rates

The following data-rate limitations apply to the slow-speed serial interfaces found in the asynchronous/synchronous serial modules:

•Asynchronous interface—Maximum data rate is 115.2 kbps.

•Synchronous interface—Maximum data rate is 128-kbps full duplex.

ISDN BRI Connections

The BRI WAN interface cards provide Integrated Services Digital Network (ISDN) Basic Rate Interface (BRI) connections. The BRI modules and BRI WAN interface cards are available with either an S/T interface that requires an external Network Termination 1 (NT1), or a U interface that has a built-in NT1.

You can install the BRI modules in any available slot in the chassis.

Warning Hazardous network voltages are present in WAN ports regardless of whether power to the unit is OFF or ON. To avoid electric shock, use caution when working near WAN ports. When detaching cables, detach the end away from the unit first. Statement 1026

Use a BRI cable (not included) to connect the BRI WAN interface card directly to an ISDN. Table 2-4lists the specifications for ISDN BRI cables. See the Cisco Modular Access Router Cable Specifications online document for pinouts. This document is available on Cisco.com.

Cisco 3700 Series Routers Hardware Installation Guide

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