Chapter 1 Product Overview
Route Processors
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Cisco 12006 and Cisco 12406 Router Installation and Configuration Guide
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Note EIA/TIA-232 is also referred to as RS-232.
The auxiliary port is an EIA/TIA-232 plug (male) that provides a data terminal
equipment (DTE) interface. The auxiliary port supports flow control and is often
used to connect a modem, a channel service unit (CSU), or other optional
equipment for Telnet management.
Note In order to maintain Class B EMI compliance, shielded cables must be used on the
console and auxiliary ports of the GRP= and GRP-B=. An updated version of the
GRP-B= board (Rev. F0) is available. This version does not require shielded
cables for Class B compliance.
Ethernet Port
The GRP has one Ethernet port (see Figure 1-4), which uses one of the following
two port connection types:
• RJ-45 receptacle—An 8-pin media-dependent interface (MDI) RJ-45
receptacle for either an IEEE 802.3 10BASE-T (10 Mbps) or an IEEE 802.3u
100BASE-TX (100 Mbps) connection.
• MII receptacle—A 40-pin media independent interface (MII) receptacle that
provides additional flexibility in Ethernet connections.
Note The RJ-45 and MII receptacles on the GRP represent two physical connection
options for one Ethernet interface: you can use either the MDI RJ-45 connection
or the MII connection, but not both simultaneously. The transmission speed of the
Ethernet port is set through an auto-sensing scheme on the GRP.
The speed is determined by the network to which the Ethernet interface is
connected, and is not user-configurable. Moreover, even at the auto-sensed data
transmission rate of 100 Mbps, the Ethernet port provides maximum usable
bandwidth of less than 100 Mbps. Expect a maximum usable bandwidth of
approximately 20 Mbps when using either the MII or RJ-45 connection.