Specifications

C-7
Cisco 7100 Series VPN Router Installation and Configuration Guide
78-6341-03
Appendix C Cable Specifications
Cisco 7120-4T1 and Cisco 7140-8T Cables and Pinouts
Figure C-4 shows the supported serial cables.
Figure C-4 T1 Serial Cables
Metric (M3) thumbscrews are included with each cable to allow connections to devices that use metric
hardware. Because the T1 ports use a special, high-density port that requires special adapter cables for
each electrical interface type, we recommend that you obtain serial interface cables from the factory.
Serial signals can travel a limited distance at any given bit rate; generally, the slower the baud rate, the
greater the distance. All serial signals are subject to distance limits beyond which a signal degrades
significantly or is completely lost.
Table C-7 lists the recommended (standard) maximum speeds and distances for each serial interface
type. The recommended maximum rate for V.35 is 2.048 Mbps.
Router connections
EIA/TIA-449 V.35 X.21
Network connections at the modem or CSU/DSU
23975
EIA/TIA-232 EIA-530
Table C-7 Recommended (Standard) Maximum Speeds and Distances for Serial Interfaces
EIA/TIA-232 Distances EIA/TIA-449, X.21, V.35, EIA-530 Distances
Rate (bps) Feet Meters Feet Meters
2400 200 60 4,100 1,250
4800 100 30 2,050 625
9600 50 15 1,025 312
19200 25 7.6 513 156
38400 12 3.7 256 78