Cisco 3725 Hardware Installation Guide - Page 44

Preparing to Connect to a Network Chapter 2 Preparing to Install the Router Table 2-3 Serial Signal Transmission Speeds and Distances Rate (bps) 2400 4800 9600 19200 38400 56000 1544000 (T1) EIA/TIA-232 Distance Feet Meters 200 60 100 30 50 15 25 7.6 12 3.7 8.6 2.6 - - EIA/TIA-449, X.21, V.35, EIA-530 Distance Feet Meters 4100 1250 2050 625 1025 312 513 156 256 78 102 31 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 2-3 are 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 2-4 lists 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. 2-12 Cisco 3700 Series Routers Hardware Installation Guide OL-2180-07