Specifications

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Cisco 7100 Series VPN Router Installation and Configuration Guide
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Chapter 2 Preparing for Installation
Safety Guidelines
If wires exceed recommended distances, or if wires pass between buildings, give special consideration
to the effect of a lightning strike in your vicinity. The electromagnetic pulse caused by lightning or other
high-energy phenomena can easily couple enough energy into unshielded conductors to destroy
electronic devices. If you have had problems of this sort in the past, you may want to consult experts in
electrical surge suppression and shielding.
Distance Limitations and Interface Specifications
The size of your networks and the distances between connections depend on the type of signal, the signal
speed, and the transmission media (the type of cabling used to transmit the signals). For example,
standard coaxial cable has a greater channel capacity than twisted-pair cabling. The distance and rate
limits in the following descriptions are the IEEE recommended maximum speeds and distances for
signaling; however, you can usually get good results at speeds and distances far greater than these. For
example, the recommended maximum rate for V.35 is 2 Mbps, but it is commonly used at 4 Mbps
without any problems. If you understand the electrical problems that might arise and can compensate for
them, you should get good results with rates and distances greater than those shown here; however, do
so at your own risk.
Note We recommend that you do not exceed specified transmission rate and distance limits.
When preparing your site for network connections to a Cisco 7100 series router, you must consider a
number of factors related to each type of interface:
• The type of cabling required for each type (fiber, thick or thin coaxial, foil-twisted pair [FTP], or
unshielded twisted-pair [UTP] cabling)
• Distance limitations for each signal type
• The specific cables you need to connect each interface
• Any additional interface equipment you need, such as transceivers, hubs, switches, modems,
channel service units (CSUs), or data service units (DSUs)
• Cable pinouts if you plan to build your cables
Note Detailed port adapter installation information is contained in the installation note for the port adapter.
For example, if you plan to replace a four-port Ethernet port adapter in your Cisco 7100 series router,
refer to the PA-4E Ethernet 10BaseT Port Adapter Installation and Configuration note. The document
is available online and on the Documentation CD-ROM.
Also see Appendix C, “Cable Specifications,” for cabling information.
Before installing a Cisco 7100 series router, have all additional external equipment and cables on hand.
For ordering information, contact a customer service representative.