Cisco 2611 - Router - EN User Manual page 30

Preparing to Connect to a Network
Although manufacturing your own serial cables is not recommended (because of the small
size of the pins on the DB-60 serial connector), cable pinouts are provided in the online
document Cisco Modular Access Router Cabling Specifications on the Documentation
CD-ROM that accompanied your router, and on Cisco Connection Online.
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 significantly degrades or is completely lost.
Note
Table 2-2 lists the recommended maximum speeds and distances for each serial interface
type; 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. For
instance, the recommended maximum rate for V.35 is 2 Mbps, but 4 Mbps is commonly
used.
Table 2-2
Rate (bps)
2400
4800
9600
19200
38400
56000
1544000 (T1)
2-16 Cisco 2600 Series Hardware Installation Guide
Only the serial WAN interface card supports bit rates above 128 kbps.
Serial Signal Transmission Speeds and Distances
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