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Chapter 3
Cable Information and Specifications for Cisco 1900 Series Routers
the shielded serial transition cable has a DB-60 connector, which connects to the DB-60 port on a serial
WIC. The other end of the serial transition cable is available with a connector appropriate for the
standard that you specify.
The synchronous serial port can be configured as DTE or DCE, depending on the attached cable (except
EIA-530, which is DTE only). To order a shielded cable, contact customer service. See the
Documentation and Submitting a Service Request" section on page
All serial ports configured as DTE require external clocking from a channel service unit/data service unit
Note
(CSU/DSU) or other DCE device.
Although we do not recommend manufacturing your own serial cables (because of the small size of the
pins on the DB-60 serial connector), cable pinouts are provided in the
Cable
Transmission Speeds and Distance Limitations
Serial signals can travel a limited distance at any given bit rate; generally, the slower the data rate, the
greater the distance. All serial signals are subject to distance limits, beyond which a signal is
significantly degraded or is completely lost.
Table 3-2
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. For instance, the recommended
maximum rate for V.35 is 2 Mbps, but 4 Mbps is commonly used.
Table 3-2
Rate (bps)
2400
4800
9600
19200
38400
56000
1544000 (T1)
Balanced drivers allow EIA/TIA-449 signals to travel greater distances than EIA/TIA-232 signals.
Typically, EIA/TIA-449 and EIA-530 can support a 2-Mbps rate, and V.35 can support a 4-Mbps rate.
Asynchronous/Synchronous Serial Module Baud Rates
The following baud-rate limitations apply to the slow-speed serial interfaces in the
asynchronous/synchronous serial modules:
•
OL-19084-01
Specifications.
lists the recommended maximum speeds and distances for each serial interface type; however,
Serial Signal Transmission Speeds and Distances
Distance for
EIA/TIA-232
Feet
Meters
200
60
100
30
50
15
25
7.6
12
3.7
8.6
2.6
—
—
Asynchronous interface—Maximum baud rate is 115.2 kbps.
Distance for
EIA/TIA-449, X.21, V.35,
and EIA-530
Distance for USB
Feet
Meters
Feet
4100
1250
16.4
2050
625
16.4
1025
312
16.4
513
156
16.4
256
78
16.4
102
31
16.4
50
15
16.4
Cisco 1900 Series Hardware Installation
Preparing to Connect to a Network
"Obtaining
xvi.
Cisco Modular Access Router
Meters
5
5
5
5
5
5
5
3-5
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