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
Console and Auxiliary Port Considerations
Cisco 7100 series routers include an asynchronous serial console and auxiliary port. The console and
auxiliary ports provide access to the access server either locally (with a console terminal) or remotely
(with a modem). This section discusses important cabling information to consider before connecting a
console terminal (an ASCII terminal or PC running terminal emulation software) to the console port or
modem to the auxiliary port.
The main difference between the console and auxiliary ports is that the auxiliary port supports hardware
(Request To Send [RTS])/Clear To Send [CTS]) flow control and the console port does not. Flow control
paces the transmission of data between a sending device and a receiving device. Flow control ensures
that the receiving device can absorb the data sent to it before the sending device sends more.
When the buffers on the receiving device are full, a message is sent to the sending device to suspend
transmission until the data in the buffers has been processed. Because the auxiliary port supports flow
control, it is ideally suited for use with the high-speed transmissions of a modem. Console terminals
transmit at slower speeds than modems; therefore, the console port is ideally suited for use with console
terminals.
For detailed information about installing a console terminal and connecting devices to the auxiliary port,
see the “Connecting the Console Port and Auxiliary Port” section on page 3-16. For cable and port
pinouts, see Appendix C, “Cable Specifications.”
Console Port Connections
Cisco 7100 series routers include an EIA/TIA-232 asynchronous serial console port (RJ-45). Depending
on the cable and the adapter used, this port will appear as a data terminal equipment (DTE) or data
communications equipment (DCE) device at the end of the cable. Your router arrives with cables and
adapters to connect a console terminal (an ASCII terminal or PC running terminal emulation software)
to the console port. To connect an ASCII terminal to the console port, use the RJ-45 rollover cable with
the female RJ-45-to-DB-25 adapter (labeled TERMINAL).
To connect a PC running terminal emulation software to the console port, use the RJ-45 rollover cable
with the female RJ-45-to-DB-9 adapter (labeled TERMINAL). The default parameters for the console
port are 9600 baud, 8 data bits, no parity, and 2 stop bits. The console port does not support hardware
flow control.
Auxiliary Port Connections
Cisco 7100 series routers include an EIA/TIA-232 asynchronous serial auxiliary port (RJ-45) that
supports flow control. Depending on the cable and the adapter used, this port will appear as a DTE or
DCE device at the end of the cable. Your router arrives with a cable and an adapter to connect a modem
to the auxiliary port. To connect a modem to the auxiliary port, use the RJ-45 rollover cable with the
male RJ-45-to-DB-25 adapter (labeled MODEM).