Chapter 2: Network Requirements2-22E42-27/2E42-27R/2E43-27/2E43-27R User’s Guide2.3 100BASE-TX NETWORKThe 2E4X-27, with an FE-100TX installed in ports 25 and 26, providesan RJ45 connection that supports UTP cabling, which has an impedanceof 85 to 111 ohms. The device at the other end of the twisted pair segmentmust meet IEEE 802.3u 100BASE-TX Fast Ethernet networkrequirements for the devices to operate at 100 Mbps. Refer to theCabletron Systems Cabling Guide for details.2.4 100BASE-FX FIBER OPTIC NETWORKPorts 25 and 26 of the 2E4X-27 support the Cabletron SystemsFE-100FX and FE-100F3 fiber optic interface modules. The device at theother end of the fiber optic segment must meet the 100BASE-FX FastEthernet network requirements to operate at 100 Mbps. Refer to theCabletron Systems Cabling Guide for details.Multimode Mode Fiber Optic Cable LengthThe maximum multimode fiber optic cable length of a 100BASE-FXsegment is covered in the Cabletron Systems Cabling Guide.Single Mode Fiber Cable LengthsThe maximum single mode fiber optic length of a 100BASE-FX segmentmay be no more than 5 km between Data Terminal Equipment (DTE toDTE) in half duplex mode or 20 km (DTE to DTE) in full duplex mode.NOTEThe 2E4X-27 with an FE-100TX installed is capable ofoperating at either 10 or 100 Mbps. The FE-100TX canautomatically sense the speed of the other device and adjustsits speed accordingly.
