Cisco CPA2501 User Manual page 30

Preparing to Connect to a Network
Ethernet model routers include an Ethernet AUI interface, which operates at speeds up to
10 Mbps.
The cables and transceivers required to connect the router to an Ethernet network are not
included. For ordering information, refer to the section "Obtaining Service and Support" in
the "Overview of the Router" chapter.
Token Ring Connections
The IEEE has established Token Ring as standard 802.5. The distance limitations for the
IEEE 802.5 specification indicate a maximum segment distance of 328 feet (100 meters)
for UTP cabling. The distance limitation is 1,640 feet (500 meters) for shielded twisted-pair
(STP) cabling.
Token Ring can operate at two different ring speeds: 4 and 16 Mbps. All devices on the ring
must agree on the operating speed.
Use a Token Ring lobe cable to connect the router to a media attachment unit (MAU). The
lobe cable and MAU are not included with the router. Refer to the section "Token Ring Port
Pinouts" in the appendix "Cable Specifications" for the Token Ring port pinouts.
Console and Auxiliary Port Connections
Your router includes an asynchronous serial console and an auxiliary port. The console and
auxiliary ports provide access to the router 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 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 ideal for use with the high-speed transmissions of
a modem. Console terminals transmit at slower speeds than modems; therefore, the console
port is ideal for use with console terminals.
2-16 Router Installation and Configuration Guide