Cisco WS-C2950T-24 Hardware Installation Guide - Page 77

Asynchronous/Synchronous Serial Module Baud Rates, ISDN BRI Connections

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Chapter 2 Preparing for Router Installation Network Cabling Specifications Table 2-3 Serial Signal Transmission Speeds and Distances Rate (bps) 2400 4800 9600 19200 38400 56000 1544000 (T1) Distance for EIA/TIA-232 Feet Meters 200 60 100 30 50 15 25 7.6 12 3.7 8.6 2.6 - - Distance for EIA/TIA-449, X.21, V.35, and EIA-530 Feet Meters 4100 1250 2050 625 1025 312 513 156 256 78 102 31 50 15 Distance for USB Feet Meters 16.4 5 16.4 5 16.4 5 16.4 5 16.4 5 16.4 5 16.4 5 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-Mb/s rates, and V.35 can support 4-Mb/s rates. Asynchronous/Synchronous Serial Module Baud Rates The following baud-rate limitations apply to the slow-speed serial interfaces found in the asynchronous/synchronous serial modules: • Asynchronous interface-Maximum baud rate is 115.2 kbps. • Synchronous interface-Maximum baud rate is 128-kbps full duplex. ISDN BRI Connections BRI WAN interface cards provide ISDN BRI connections. The BRI modules and BRI WAN interface cards are available with either an S/T interface that requires an external Network Terminator 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. Also, see the Cisco Modular Access Router Cable Specifications document at Cisco.com for pinouts. OL-18712-02 Cisco 2900 Series and 3900 Series Hardware Installation Guide 2-11

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2-11
Cisco 2900 Series and 3900 Series Hardware Installation Guide
OL-18712-02
Chapter 2
Preparing for Router Installation
Network Cabling Specifications
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-Mb/s rates, and V.35 can support 4-Mb/s
rates.
Asynchronous/Synchronous Serial Module Baud Rates
The following baud-rate limitations apply to the slow-speed serial interfaces found in the
asynchronous/synchronous serial modules:
Asynchronous interface—Maximum baud rate is 115.2 kbps.
Synchronous interface—Maximum baud rate is 128-kbps full duplex.
ISDN BRI Connections
BRI WAN interface cards provide ISDN BRI connections. The BRI modules and BRI WAN interface
cards are available with either an S/T interface that requires an external Network Terminator 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. Also, see the
Cisco Modular Access Router Cable
Specifications
document at Cisco.com for pinouts.
Table 2-3
Serial Signal Transmission Speeds and Distances
Distance for
EIA/TIA-232
Distance for
EIA/TIA-449, X.21, V.35,
and EIA-530
Distance for USB
Rate (bps)
Feet
Meters
Feet
Meters
Feet
Meters
2400
200
60
4100
1250
16.4
5
4800
100
30
2050
625
16.4
5
9600
50
15
1025
312
16.4
5
19200
25
7.6
513
156
16.4
5
38400
12
3.7
256
78
16.4
5
56000
8.6
2.6
102
31
16.4
5
1544000 (T1)
50
15
16.4
5